OBD I - Vikakoodien selityksiä

GM Vikakoodit 1982 - 1996


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GM

82-83 2.5 L

13 Oxygen sensor circuit
14 Coolant temperature sensor voltage low
15 Coolant temperature sensor voltage high
21 TPS voltage was above 2.5 volts for 10 seconds when the MAP sensor signal showed
     manifold vacuum to be 15 pounds or more with
     an engine speed less than 1300 RPM.
22 TPS voltage was under 0.2 volts for 4 seconds when the engine was running.
24 Vehicle Speed sensor circuit
33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle
     opening was 2%.
42 The EST signal did not change when the ECM applied bypass
    voltage to the ignition module. 44 Oxygen sensor lean exhaust indication.
45 Oxygen sensor rich exhaust indication.
51 PROM not reading.
55 ECM problem


GM

82-83 3.0L

13 Oxygen sensor circuit
14 Coolant temperature sensor voltage low
15 Coolant temperature sensor voltage high
21 TPS voltage was above 2.5 volts for 10 seconds when the MAP sensor
     signal showed manifold vacuum to be 15 pounds or more with an engine speed
     less than 1300 RPM.
23 Open or grounded M/C (mixture control) solenoid circuit.
24 Vehicle Speed sensor circuit
32 BARO sensor voltage too low
33 MAP sensor signal voltage was too high (low vacuum) for
     5 seconds when throttle opening was under 2%.
35 Shorted ISC Motor Throttle Switch
41 No distributer referance signal
42 The EST signal did not change when the ECM applied bypass voltage
     to the ignition module.
43 Voltage at ECM terminal "L" low.
44 Oxygen sensor circuit.
45 Oxygen sensor rich exhaust indication.
51 PROM not reading.
54 Constant High Voltage From M/C Solenoid To ECM.
55 ECM problem

GM

86 1.8L VIN J MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds.
     Engine was at normal operating temperature and had been running
     for at least 1 minute after start with a throttle
     angle above 6.5%.
14 Coolant temperature sensor signal indicates a temperature
     of over 275° F for 3 seconds.
15 Coolant temperature sensor signal indicates a temperature colder
     than -22° F after engine had been running for 50 seconds.
21 TPS voltage was above 2.5 volts for 10 seconds when the
     MAP sensor signal showed manifold vacuum
     to be 15 pounds or more with an engine speed less than 1300 RPM.
22 TPS voltage was under 0.2 volts for 4 seconds
     when the engine was running.
23 Manifold air temperature sensor signal showed an air temperature
     below -22° F for 10 seconds.
24 When engine speed was between 1400 and 4400 RPM, the MAP
     signal showed low voltage (high manifold vacuum) for at least 5 seconds.
25 Inlet air temperature sensor signal showed an air temperature over 275° F for
     more than 30 seconds.
31 Manifold pressure exceeded 8 psi of boost for 2 seconds.
32 EGR open command did not change the fuel mixture when the command
     was given during off idle operation. EGR opening should cause the mixture to be
    slightly richer because of the low oxygen content of exhaust gas.
33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds
     when throttle opening was under 2%.
34 MAP sensor signal voltage was too low (high vacuum) when engine
    speed was below 1200 RPM and TPS was greater than 20%.
35 Idle speed was 225 RPM above desired speed for 20 seconds.
42 The EST signal did not change when the ECM applied bypass
     voltage to the ignition module.
43 Knock sensor circuit voltage was above 3.5 volts or below
     1.5 volts for 5 seconds.
44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed
     loop operation.
45 Oxygen sensor voltage was over 0.75 volts for 50 seconds or more in closed
     loop operation.

GM

86 1.8L VIN 0 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for
     3 seconds during closed loop operation and will set code after 40 seconds
     for Century and Cutlass Ciera. For the Lumina, the oxygen sensor
     voltage stays between 0.35 and 0.55
     volts for 60 seconds during closed loop operation and will set code after 2 minutes.
     Both systems can go into open loop after 15 seconds.
14 Coolant temperature sensor signal indicates a temperature
     of over 275° F for 3 seconds.
15 Coolant temperature sensor signal indicates a temperature colder
     than -22° F after the engine has been running for 2 minutes.
21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed
    manifold vacuum to be 15 pounds or more under 1800 RPM.
22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running.
23 Inlet air temperature sensor signal showed an air temperature of -22° F after
     the engine has been running for 1 minute.
24 The following conditions must be met for 5 seconds: Throttle position
     signal was less than 2% with engine speed between 1400 and 4400 RPM
    and the MAP signal showed low voltage and high manifold vacuum.
     Transmission was not in park or neutral.
25 Inlet air temperature sensor signal showed an air temperature over 275° F
    for more than 2 seconds after the engine has been running for 5 minutes
     and vehicle speed was greater than 44 MPH.
32 EGR open command did not change the fuel mixture when the command was given during
     off idle operation. EGR opening should cause the mixture to be slightly
     richer because of the low oxygen content of exhaust gas.
33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle
     opening was under 2%.
34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200
     RPM or when engine speed was over 1200
     RPM with throttle opening was over 20%.
35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM.
42 The EST signal did not change when the ECM applied bypass voltage to the ignition module.
44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation.
45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over
     0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts for 30 seconds
     and throttle angle was between 3% and 45%.
51 PROM error.
53 Charging system voltage was greater than 16.9 volts for more than 50 seconds.
     Repair charging system

www.handen.us GM

86 2.0L VIN P TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed
     loop operation, and will set code after 40 seconds for Century and Cutlass Ciera.
     For the Lumina, the oxygen sensor voltage stays between 0.35 and 0.55 volts for
     60 seconds during closed loop operation and will set code after 2 minutes.
     Both systems can go into open loop after 15 seconds.
14 Coolant temperature sensor signal indicates a temperature of over 275° F
     for 3 seconds.
15 Coolant temperature sensor signal indicates a temperature colder than
     -22° F after the engine has been running for 2 minutes.
21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed
     manifold vacuum to be 15 pounds or more under 1800 RPM.
22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running.
23 Inlet air temperature sensor signal showed an air temperature of
     -22° F after the engine has been running for 1 minute.M/C Solenoid Circuit Open Or
     Grounded
24 Vehicle Speed Sensor Sensor/Circuit.The following conditions must be met for
     5 seconds: Throttle position signal was less than 2% with engine speed
     between 1400 and 4400 RPM and the MAP signal showed low voltage and high
     manifold vacuum. Transmission was not in park or neutral.
     275° F for more than 2 seconds after the engine has been running
     for 5 minutes and vehicle speed was greater than 44 MPH.
32 EGR open command did not change the fuel mixture when the command was given during
     off idle operation. EGR opening should cause the mixture to be slightly
     richer because of the low oxygen content of exhaust gas.
33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when
     throttle opening was under 2%.
34 MAP sensor signal voltage was too low (high vacuum) when engine speed was
     under 1200 RPM or when engine speed was over 1200 RPM with throttle opening over 20%.
35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM.
42 The EST signal did not change when the ECM applied bypass voltage to the ignition module.
44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation.
45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was
     over 0.750 volts for 50 seconds in a closed loop. Lumina was over
     0.700 volts for 30 seconds and throttle angle was between 3% and 45%.
51 PROM error.
53 Charging system voltage was greater than 16.9 volts for more than 50 seconds.
     Repair charging system

    

GM

1986 2.5L VIN 2 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during
     closed loop operation and will set code after 40 seconds for Century and Cutlass Ciera.
     For the Lumina, the oxygen sensor voltage stays between 0.35 and 0.55 volts
     for 60 seconds during closed loop operation and will set code after
     2 minutes. Both systems can go into open loop after 15 seconds.
14 Coolant temperature sensor signal indicates a temperature of over 275° F
    for 3 seconds.
15 Coolant temperature sensor signal indicates a temperature colder than
     -22° F after the engine has been running for 2 minutes.
21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed
     manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under
     0.2 volts for 2 seconds when the engine was running.
23 Inlet ATS signal showed an air temperature of -22° F after the engine has
     been running for 1 minute.
24 TPS signal was less than 2% with engine speed between 1400 and 4400 RPM and the
     MAP signal showed low voltage and high manifold vacuum. Transmission was not in park
     or neutral.
25 Inlet ATS signal showed an air temperature over 275° F for more than 2 seconds
     after the engine has been running for 5 minutes and vehicle speed was greater
     than 44 MPH.
32 EGR open command did not change the fuel mixture when the command was given
     during off idle operation. EGR opening should cause the mixture to be slightly
     richer because of the low oxygen content of exhaust gas.
33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when
     throttle opening was under 2%.
34 MAP sensor signal voltage was too low (high vacuum) when engine speed was
     under 1200 RPM or when engine speed was over 1200 RPM with throttle opening
     was over 20%.
35 Idle speed was over 150 RPM outside the desired engine speed commanded by
    the ECM.
42 The EST signal did not change when the ECM applied bypass voltage to the ignition
    module.
44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation.
45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was
     over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts
     for 30 seconds and throttle angle was between 3% and 45%.
51 PROM error.
53 Charging system voltage was greater than 16.9 volts for more than 50 seconds.
     Repair charging system

GM

86 2.8L VIN X Carb

12 ECM did not receive distributor reference pulses when cam pulses were
     being received.
13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds
     during closed loop operation after the engine had been running for 4 minutes
     and the throttle angle was above 4%.
14 Coolant temperature sensor was shorted showing a high temperature after
     engine had been running for 2 minutes.
15 Coolant temperature sensor was open showing a low temperature after
     engine had been running for 5 minutes.
21 TPS was open showing low voltage.
22 TPS voltage was under 0.2 volts for 3 seconds when the engine was running.
23 Mixture control solenoid circuit was either open or shorted.
24 Vehicle speed sensor was out of range after vehicle had been at road speed
     for 2 minutes.
32 Barometric pressure sensor circuit was low.
34 MAP sensor or vacuum sensor was open or shorted.
35 Idle speed control switch circuit was shorted showing a high TPS reading
     for over 5 seconds.
41 ECM did not see any distributor reference pulses.
42 The EST signal did not change when the ECM applied bypass voltage to
     the ignition module.
43 The ESC knock signal lasted too long causing the EST signal to be retarded.
44 Oxygen sensor was lean during closed loop operation after engine had been
     running for 2 minutes.
45 Oxygen sensor was rich during closed loop operation after engine had been
     running for 2 minutes.
51 PROM error.
53 EGR valve vacuum was incorrect.
54 Mixture control solenoid circuit was shorted and/or ECM is faulty

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GM

86 3.8L VIN B

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110° F. 14 Coolant temperature sensor signal indicates a temperature of over 284? F for 4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36° F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was either below 9 volts or above 16 volts for 10 seconds. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.1 volts for 4 seconds when the ignition was on. 23 Inlet air temperature sensor signal showed an air temperature of -40° F for 4 seconds. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds when vehicle was in 4th gear. 25 Inlet air temperature sensor signal showed an air temperature of over 275° F for 16 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 31 PRNDL indicates a gear other than park or neutral for 13 seconds for 3 consecutive startups when ignition was on, engine was off and vehicle speed was 0. Or the PRNDL status indicators (A, B, C, P) showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 38 The Torque Converter Clutch portion of the brake switch was open and caused the TCC to be inoperative. 39 The torque converter clutch portion of the brake switch was inoperative for 30 seconds causing vehicle speed ratio to be outside of its window of operation. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 51 MEM-CAL error. 63 EGR flow was incorrect. EGR solenoid did not work properly. 64 EGR flow was incorrect. EGR solenoid did not work properly. 65 EGR flow was incorrect. EGR solenoid did not work properly GM
86-87 3.8L VIN A Carb

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27° F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22° F after the engine has been running for 5 minutes. 24 Vehicle Speed Sensor Sensor/Circuit.When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302° F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR Flow should cause slight decrease in manifold vacuum, which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
86-87 4.1L VIN 8 FI

12 PCM did not receive distributor reference pulses for 2.1 seconds. 13 Oxygen sensor voltage stays between 0.275 and 0.63 volts for 40 seconds (30 seconds for Eldorado & Seville). 14 Coolant temperature sensor signal indicates a temperature of over 313° F. 15 Coolant temperature sensor signal indicates a temperature colder than -32° F. 16 Generator voltage was either less than 10 volts or greater than 16 volts for 5 seconds. 18 Crankshaft sensor signal was not received by ECM. 19 Fuel pump feedback voltage stayed above 11 volts for 7 seconds after ignition was turned on (except Eldorado & Seville). 20 Fuel pump feedback voltage was 2 volts or less for 3 seconds. 21 TPS value was 83 degrees or more for 1.5 seconds (80 degrees or more for 3 seconds on Eldorado & Seville). 22 TPS value was 6 degrees or less for 1.5 seconds when the engine was running at 600 RPM or more. 23 EST signal did not change when the ECM applied bypass voltage to the ignition module. 24 Vehicle speed was 0 for 3 seconds with transmission in drive or reverse and brake off when throttle angle was at least 17 degrees and engine RPM was 1400 or greater. 26 Throttle switch input to the PCM was closed for 1.8 seconds while the TPS was between 15 and 83 degrees. 27 Throttle switch was open when vehicle was at coasting down with brake applied. Throttle angle was 12 degrees or less but RPM was greater than desired. 28 3rd or 4th gear input to ECM was not grounded when vehicle was in park or neutral. 30 TPS was 1.7 degrees (2.5 degrees on Eldorado & Seville) or more while ISC was retracting for 15 seconds, or TPS was less than 12.75 degrees (9 degrees on Eldorado & Seville) while ISC was extending for 15 seconds. 31 MAP sensor was shorted to 5 volts for 0.2 seconds. 32 MAP sensor was open showing a reading of 0.5 volts or less for 0.2 seconds. 34 MAP sensor signal voltage was too high (low vacuum) for 2 seconds when throttle switch was closed. 37 MAT sensor was shorted showing a temperature of 313° F or more. 38 MAT sensor was open showing a temperature of -27° F or less. 39 Engine RPM was outside of the range expected for indicated vehicle speed indicating a VCC engagement problem. 40 Power steering switch was open for 10 seconds when vehicle was at a speed of 40 MPH or greater. 44 Oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater. 45 Oxygen sensor was rich for more than 50 seconds when engine was warm and at 800 RPM or greater. 47 ECM has received bad data from BCM for 2.1 seconds. 48 EGR open command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. Vehicle speed was over 35 MPH and engine was warm. 52 ECM has lost primary battery power. 53 Distributor reference pulses were not received for 0.7 seconds when engine speed was greater than 448 RPM. 55 TPS zero point was out of range. 58 Pass Key fuel enable was not correct. (Eldorado & Seville only) 59 Transmission temperature was either above 335° F or below 104° F. 60 Transmission was not in drive when cruise control was engaged. 63 Vehicle speed was 20 MPH higher than the set speed for 0.5 seconds with cruise control on. 64 Vehicle speed increased more than 16 MPH (6 MPH on Eldorado & Seville) in 1 second while cruise control was engaged. 65 Coolant temperature was above 289° F when cruise control was engaged. 66 Engine RPM was 4800 or more for 0.25 seconds with cruise control engaged. 67 Cruise control Set/Coast or Resume/Accel signal was present when the cruise ON/OFF switch was turned on or Set/Coast and Resume/Accel signals were present at the same time GM
86-87 5.0L VIN 9 Carb

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27° F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22° F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302° F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM GM
1986-1988 2.5L VIN U TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed loop operation and will set code after 40 seconds for Century and Cutlass Ciera. For the Lumina, the oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation and will set code after 2 minutes. Both systems can go into open loop after 15 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22° F after the engine has been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet ATS signal showed an air temperature of -22° F after the engine has been running for 1 minute. 24 Vehicle Speed Sensor Sensor/Circuit. Throttle position signal was less than 2% with engine speed between 1400 and 4400 RPM and the MAP signal showed low voltage and high manifold vacuum. Transmission was not in park or neutral. 25 Inlet ATS signal showed an air temperature over 275° F for more than 2 seconds after the engine has been running for 5 minutes and vehicle speed was greater than 44 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 20%. 35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts for 30 seconds and throttle angle was between 3% and 45%. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for more than 50 seconds. Repair charging system GM
1986-1988 2.5L VIN R TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed loop operation and will set code after 40 seconds for Century and Cutlass Ciera. For the Lumina, the oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation and will set code after 2 minutes. Both systems can go into open loop after 15 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22° F after the engine has been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -22° F after the engine has been running for 1 minute. 24 Vehicle Speed Sensor Sensor/Circuit. Throttle position signal was less than 2% with engine speed between 1400 and 4400 RPM and the MAP signal showed low voltage and high manifold vacuum. Transmission was not in park or neutral. 25 Inlet air temperature sensor signal showed an air temperature over 275° F for more than 2 seconds after the engine has been running for 5 minutes and vehicle speed was greater than 44 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 20%. 35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts for 30 seconds and throttle angle was between 3% and 45%. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for more than 50 seconds. Repair charging system GM
86-88 2.8L VIN 9 MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation after the engine had been running for 2 minutes and the throttle angle was above 4%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -47° F for 3 seconds. 21 TPS voltage was above 2.5 volts for 5 seconds when the MAP sensor signal showed manifold vacuum above 15 pounds or TPS signal voltage was over 4.5 volts. 22 TPS voltage was under 0.2 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature of -31° F for 3 seconds after the engine has been running for 8 minutes. 24 Vehicle Speed Sensor Sensor/Circuit.When engine speed was between 1400 and 3600 RPM and throttle angle was less than 2%, the MAP sensor signal showed low voltage (High manifold vacuum) for at least 3 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293° F for more than 3 seconds after the engine has been running for 4 minutes and a vehicle speed was present. 32 EGR vacuum switch was closed during start-up or idle, or EGR vacuum switch did not close when EGR solenoid was commanded to close by ECM for 5 seconds. 33 MAF sensor indicated air flow was more than 20 gm/sec for 2 seconds. 34 MAF sensor signal showed air flow to be less than 2 gm/sec, or the MAF circuit was shorted. 41 The number of crank reference pulses did not match the number according to the PROM when engine speed was under 2000 RPM, or the incorrect PROM has been installed. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds in a closed loop when throttle angle was between 3% and 45% and engine had been running for at least 1 minute. 51 PROM error. 52 CALPAK error. 53 Charging system voltage was greater than 17.1 volts for 2 seconds. Repair charging system. 54 Fuel pump signal voltage was less than 2 volts for 1.5 seconds. 55 ECM error. Replace ECM. GM
86-88 3.0L VIN L MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110° F. 14 Coolant temperature sensor signal indicates a temperature of over 284° F for 4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36° F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was either below 9 volts or above 16 volts for 10 seconds. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS was under 0.1 volts for 4 seconds when the ignition was on. 23 Inlet air temperature sensor signal showed an air temperature of -40? F for 4 seconds. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds when vehicle was in 4th gear. 25 Inlet air temperature sensor signal showed an air temperature of over 275° F for 16 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 31 PRNDL indicates a gear other than park or neutral for 13 seconds for 3 consecutive startups when ignition was on and engine was off and vehicle speed was 0. Or the PRNDL status indicators showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 38 The Torque Converter Clutch (TCC) portion of the brake switch was open and caused the TCC to be inoperative. 39 The TCC portion of the brake switch was inoperative for 30 seconds causing vehicle speed ratio to be outside of its window of operation. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 51 MEM-CAL error. 63 EGR flow was incorrect. EGR solenoid did not work properly. 64 EGR flow was incorrect. EGR solenoid did not work properly. 65 EGR flow was incorrect. EGR solenoid did not work properly. GM
86-88 3.8L VIN 7

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110° F. 14 Coolant temperature sensor signal indicates a temperature of over 284° F for 4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36° F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was either below 9 volts or above 16 volts for 10 seconds. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.1 volts for 4 seconds when the ignition was on. 23 Inlet air temperature sensor signal showed an air temperature of -40° F for 4 seconds. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds when vehicle was in 4th gear. 25 Inlet air temperature sensor signal showed an air temperature of over 275° F for 16 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 31 PRNDL indicates a gear other than park or neutral for 13 seconds for 3 consecutive startups when ignition was on, engine was off and vehicle speed was 0. Or the PRNDL status indicators (A, B, C, P) showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 38 The Torque Converter Clutch portion of the brake switch was open and caused the TCC to be inoperative. 39 The torque converter clutch portion of the brake switch was inoperative for 30 seconds causing vehicle speed ratio to be outside of its window of operation. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 51 MEM-CAL error. 63 EGR flow was incorrect. EGR solenoid did not work properly. 64 EGR flow was incorrect. EGR solenoid did not work properly. 65 EGR flow was incorrect. EGR solenoid did not work properly GM
86-88 3.8L VIN 3

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110° F. 14 Coolant temperature sensor signal indicates a temperature of over 284° F for 4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36° F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was either below 9 volts or above 16 volts for 10 seconds. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.1 volts for 4 seconds when the ignition was on. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds when vehicle was in 4th gear. 29 4th gear switch was closed or grounded when vehicle was in 4th gear, or 4th gear switch was open when engine was first started. 32 EGR valve did not change when the command was given during off-idle operation. 33 MAP signal was too high (low vacuum) when engine was at normal operating temperature. 34 There was no MAF signal for over 4 seconds while engine was running. 37 MAT sensor was shorted showing a high temperature of around 300° F. 38 The Torque Converter Clutch portion of the brake switch was open and caused the TCC to be inoperative. 40 Power steering switch was open when vehicle speed was 40 MPH or more. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 47 Momentary loss of power to Body Computer Module (BCM). 51 MEM-CAL error. 52 CALPAK error. 55 ECM error. Replace ECM GM
86-88 5.0L VIN H Carb

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27° F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22° F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302° F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM GM
86-88 5.0L VIN G Carb

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27° F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22° F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302° F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
86-88 5.7L VIN 8

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 266° F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38° F for 3 seconds. 21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.5 volts at any time. 22 TPS voltage was under 0.2 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22° F for 12 seconds after the engine has been running for 5 minutes. 24 Vehicle was not in park or neutral while engine speed was between 900 and 4400 RPM for 2 seconds with throttle closed. 25 Manifold air temperature sensor signal showed an air temperature over 302° F for 12 seconds after the engine has been running for 4 minutes and vehicle speed was above 5 MPH. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 1 second when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 600 RPM or the engine speed was over 600 RPM with a throttle position angle above 6%. 36 MAF sensor burn-off voltage was missing. Check MAF sensor burn-off relay and terminal "D" on MAF. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation. 43 The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle above 2%. The engine was running for at least 1 minute. 46 ECM did not receive the proper signal from vehicle anti-theft system when ignition was turned on. 51 MEM-CAL error. 52 CALPAK error. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received GM
86-88 5.7L VIN 6 Carb

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27° F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS was above 2.5 volts for 8 seconds when the MAP sensor signal l showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22° F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302° F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM GM
86-89 2.8L VIN W MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation after the engine had been running for 2 minutes and the throttle angle was above 4%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -47° F for 20 seconds. 21 TPS voltage was above 4.3 volts for 10 seconds when the MAP sensor signal showed manifold vacuum above 15 pounds, or TPS signal voltage was over 4.5 volts. 22 TPS voltage was under 0.25 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature of -31° F for 4 seconds after the engine has been running for 8 minutes. 24 When engine speed was between 1400 and 3600 RPM and throttle angle was less than 2%, the MAP sensor signal showed low voltage (High manifold vacuum) for at least 5 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293° F for more than 3 seconds after the engine has been running for 4 minutes and a vehicle speed was present. 32 EGR open command did not change the fuel mixture when the command was given during off-idle operation. 33 MAP sensor signal was too high (low vacuum) for 2 seconds when throttle angle was less than 2%. 34 MAP sensor signal was too low (high vacuum) when engine speed was less than 600 RPM, or MAP sensor signal was too low (high vacuum) when throttle angle was over 20%. 35 Engine idle speed was either below or above desired speed by 300 RPM for 50 seconds. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either above 3.5 volts or below 1.5 volts for 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds in a closed loop when throttle angle was between 3% and 45% and engine had been running for at least 1 minute. 51 PROM error. 52 CALPAK error. 53 Charging system voltage was greater than 17.1 volts for 2 seconds. Repair charging system. 54 Fuel pump signal voltage was less than 2 volts for 1.5 seconds. GM
86-89 2.8L VIN S MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation after the engine had been running for 2 minutes and the throttle angle was above 4%. 14 Coolant temperature sensor signal indicates a temperature of over 275° F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -47° F for 3 seconds. 21 TPS voltage was above 2.5 volts for 5 seconds when the MAP sensor signal showed manifold vacuum above 15 pounds or TPS signal voltage was over 4.5 volts. 22 TPS voltage was under 0.2 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature of -31° F for 3 seconds after the engine has been running for 8 minutes. 24 When engine speed was between 1400 and 3600 RPM and throttle angle was less than 2%, the MAP sensor signal showed low voltage (High manifold vacuum) for at least 3 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293° F for more than 3 seconds after the engine has been running for 4 minutes and a vehicle speed was present. 32 EGR vacuum switch was closed during start-up or idle, or EGR vacuum switch did not close when EGR solenoid was commanded to close by ECM for 5 seconds. 33 MAF sensor indicated air flow was more than 20 gm/sec for 2 seconds. 34 MAF sensor signal showed air flow to be less than 2 gm/sec or the MAF circuit was shorted. 41 The number of crank reference pulses did not match the number according to the PROM when engine speed was under 2000 RPM, or the incorrect PROM has been installed. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds in a closed loop when throttle angle was between 3% and 45% and engine had been running for at least 1 minute. 51 PROM error. 52 CALPAK error. 53 Charging system voltage was greater than 17.1 volts for 2 seconds. Repair charging system. 54 Fuel pump signal voltage was less than 2 volts for 1.5 seconds. 55 ECM error. Replace ECM. GM
86-89 5.0L VIN F

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 3 seconds. 21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.8 volts at anytime. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1400 and 3600 RPM and throttle position angle was less than 2% for at least 4 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 2 seconds after the engine has been running for 2 minutes and vehicle speed was greater than 5 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAF sensor indicated an air flow of 45 gm/sec or more for 1 second when TPS was less than 1/4 throttle and engine speed was under 2000 RPM. 34 MAF sensor indicated an air flow of 25 gm/sec or less for 1 second when TPS was above 6% and engine speed was above 2300 RPM. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds with a throttle angle above 2%. 51 MEM-CAL error. 52 CALPAK error. 53 ECM sees a battery voltage of more than 17.1 volts for 2 seconds. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received GM
86-90 4.3L VIN Z TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the, engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM, or the throttle angle was above 21% when engine speed was over 1200 RPM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds after engine had been running for 1 minute with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
87-88 2.0L VIN 1 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed loop operation and will set code after 40 seconds for Century and Cutlass Ciera. For the Lumina, the oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation and will set code after 2 minutes. Both systems can go into open loop after 15 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after the engine has been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -22? F after the engine has been running for 1 minute. 24 The following conditions must be met for 5 seconds: Throttle position signal was less than 2% with engine speed between 1400 and 4400 RPM and the MAP signal showed low voltage and high manifold vacuum. Transmission was not in park or neutral. 25 Inlet air temperature sensor signal showed an air temperature over 275? F for more than 2 seconds after the engine has been running for 5 minutes and vehicle speed was greater than 44 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 20%. 35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts for 30 seconds and throttle angle was between 3% and 45%. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for more than 50 seconds. Repair charging system GM
87 2.8L VIN R TBI

13 Oxygen Sensor Open Circuit Open circuit 14 Coolant Temperature Sensor Circuit High temp indicated 15 Coolant Temperature Sensor Circuit Low Temp indicated 21 Throttle Position Sensor (TPS) Circuit (Signal Voltage High) 22 Throttle Position Sensor (TPS) Circuit (Signal Voltage Low) 24 VSS Circuit Fault 32 EGR System Failure 33 MAP Sensor Circuit Signal Voltage High (Low Vacuum) 34 MAP Sensor Circuit Signal Voltage Low (High Vacuum) 42 Electronic Spark Timing (EST) 43 Electronic Spark Control (ESC) Circuit 44 Lean Exhaust Indicated 45 Rich Exhaust Indicated 51 FAULTY MEM-CAL OR PROM PROBLEM 52 FUEL CALPAK MISSING 53 VOLTAGE AT ECM TERMINAL B1 IS GREATER THAN 17.1 VOLTS FOR 2 SECONDS. 54 Fuel Pump Circuit (Low Voltage) 55 FAULTY ECM GM
87-88 4.1L VIN 7 MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation after the engine had been running for 2 minutes and the throttle angle was above 4%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -47? F for 20 seconds. 21 TPS voltage was above 4.3 volts for 10 seconds when the MAP sensor signal showed manifold vacuum above 15 pounds, or TPS signal voltage was over 4.5 volts. 22 TPS voltage was under 0.25 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature of -31? F for 4 seconds after the engine has been running for 8 minutes. 24 When engine speed was between 1400 and 3600 RPM and throttle angle was less than 2%, the MAP sensor signal showed low voltage (High manifold vacuum) for at least 5 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293? F for more than 3 seconds after the engine has been running for 4 minutes and a vehicle speed was present. 32 EGR open command did not change the fuel mixture when the command was given during off-idle operation. 33 MAP sensor signal was too high (low vacuum) for 2 seconds when throttle angle was less than 2%. 34 MAP sensor signal was too low (high vacuum) when engine speed was less than 600 RPM, or MAP sensor signal was too low (high vacuum) when throttle angle was over 20%. 35 Engine idle speed was either below or above desired speed by 300 RPM for 50 seconds. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either above 3.5 volts or below 1.5 volts for 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds in a closed loop when throttle angle was between 3% and 45% and engine had been running for at least 1 minute. 51 PROM error. 52 CALPAK error. 53 Charging system voltage was greater than 17.1 volts for 2 seconds. Repair charging system. 54 Fuel pump signal voltage was less than 2 volts for 1.5 seconds. GM
87-90 2.0L VIN M MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 1 minute after start with a throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 2.5 volts for 10 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more with an engine speed less than 1300 RPM. 22 TPS voltage was under 0.2 volts for 4 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F for 10 seconds. 24 When engine speed was between 1400 and 4400 RPM, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 275? F for more than 30 seconds. 31 Manifold pressure exceeded 8 psi of boost for 2 seconds. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was below 1200 RPM and TPS was greater than 20%. 35 Idle speed was 225 RPM above desired speed for 20 seconds. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor circuit voltage was above 3.5 volts or below 1.5 volts for 5 seconds. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds or more in closed loop operation GM
87-90 5.0L VIN Y

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
87-91 2.0L VIN K TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds. Engine was at normal operating temperature and had been running for at least 40 seconds after start with a throttle angle above 7%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more with an engine speed less than 1800 RPM. 22 TPS voltage was under 0.2 volts when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -31? F after the engine had been running for 2 minutes (9 minutes for Beretta & Corsica engine). 24 When engine speed was between 1400 and 4400 RPM, the MAP signal showed low voltage (high manifold vacuum) for at least 3 seconds (5 seconds for Beretta & Corsica). 25 Inlet air temperature sensor signal showed an air temperature over 275? F for more than 2 seconds. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was above 1200 RPM and TPS was greater than 20%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds or more in closed loop operation. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for 10 seconds. Repair charging system GM
88-89 2.3L VIN D MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds at throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds after engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either below 1.25 volts or above 3.75 volts for 5 seconds, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle was in park or neutral at a speed less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear for 20 seconds. 65 Fuel injector driver current did not reach 4 amps, injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. 66 A/C refrigerant pressure voltage was either less than 0.1 volts, or more than 4.9 volts for 5 seconds. GM
88-89 3.1L VIN T MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds when the TPS signal was above 4%. The engine had been running for at least 2 minutes. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for at least 20 seconds. 21 TPS voltage was above 4.3 volts for 10 seconds when engine was running and air flow was less than 17 gm/sec. 22 TPS voltage was under 0.25 volts for 4 seconds when the ignition was on. 23 Manifold air temperature sensor signal showed an air temperature of -31? F for 10 seconds after engine had been running for 4 minutes. 24 Engine speed was between 2200 and 4400 RPM and transmission was not in park or neutral and TPS was less than 2% for 3 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293? F for 3 seconds when vehicle speed was greater than 3 MPH and engine had been running for 8 minutes. 26 Quad-driver sense voltage showed a low voltage when battery voltage should be present, or the sense voltage showed battery voltage when a low voltage should be present. 32 The ECM opens each EGR control valve during deceleration and monitors the change in manifold vacuum. The code sets when the change in manifold vacuum is outside the normal range. 33 MAP sensor voltage was too high for 4.8 seconds when throttle angle was less than 2%. 34 MAP sensor voltage was too low for 1 second when engine speed was under 600 RPM, or MAP sensor voltage was too low for 1 second when engine speed was over 600 RPM and throttle angle was above 20%. 41 Faulty or incorrect MEM-CAL. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for at least 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds in closed loop operation with a throttle angle between 3% and 45%. 51 MEM-CAL error. 52 CALPAK error. 53 ECM sees a battery voltage of more than 17.1 volts for 2 seconds. 54 Fuel pump voltage was less than 4 volts for 0.4 seconds. 62 Vehicle gear commanded by ECM did not match actual gear selected. 66 A/C pressure sensor voltage was either above 4.9 volts or below 0.1 volts for at least 5 seconds. GM
88-89 4.5L VIN 5

12 PCM did not receive distributor reference pulses for 2.1 seconds. 13 Oxygen sensor voltage stays between 0.275 and 0.630 volts for 40 seconds (30 seconds for Eldorado & Seville). 14 Coolant temperature sensor signal indicates a temperature of over 313? F. 15 Coolant temperature sensor signal indicates a temperature colder than -32? F. 16 Generator voltage was either less than 10 volts or greater than 16 volts for 5 seconds. 18 Crankshaft sensor signal was not received by ECM. 19 Fuel pump feedback voltage stayed above 11 volts for 7 seconds after ignition was turned on (except Eldorado & Seville). 20 Fuel pump feedback voltage was 2 volts or less for 3 seconds. 21 TPS value was 83 degrees or more for 1.5 seconds (80 degrees or more for 3 seconds on Eldorado & Seville). 22 TPS value was 6 degrees or less for 1.5 seconds when the engine was running at 600 RPM or more. 23 EST signal did not change when the ECM applied bypass voltage to the ignition module. 24 Vehicle speed was 0 for 3 seconds with transmission in drive or reverse and brake off when throttle angle was at least 17 degrees and engine RPM was 1400 or greater. 26 Throttle switch input to the PCM was closed for 1.8 seconds while the TPS was between 15 and 83 degrees. 27 Throttle switch was open when vehicle was at coasting down with brake applied. Throttle angle was 12 degrees or less but RPM was greater than desired. 28 3rd or 4th gear input to ECM was not grounded when vehicle was in park or neutral. 30 TPS was 1.7 degrees or more (2.5 degrees on Eldorado & Seville) while ISC was retracting for 15 seconds, or TPS was less than 12.75 degrees (9 degrees on Eldorado & Seville) while ISC was extending for 15 seconds. 31 MAP sensor was shorted to 5 volts for 0.2 seconds. 32 MAP sensor was open showing a reading of 0.5 volts or less for 0.2 seconds. 34 MAP sensor signal voltage was too high (low vacuum) for 2 seconds when throttle switch was closed. 37 MAT sensor was shorted showing a temperature of 313? F or more. 38 MAT sensor was open showing a temperature of -27? F or less. 39 Engine RPM was outside of the range expected for indicated vehicle speed indicating a VCC engagement problem. 40 Power steering switch was open for 10 seconds when vehicle was at a speed of 40 MPH or greater. 44 Oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater. 45 Oxygen sensor was rich for more than 50 seconds when engine was warm and at 800 RPM or greater. 47 ECM has received bad data from BCM for 2.1 seconds. 48 EGR open command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. Vehicle speed was over 35 MPH and engine was warm. 52 ECM has lost primary battery power. 53 Distributor reference pulses were not received for 0.7 seconds when engine speed was greater than 448 RPM. 55 TPS zero point was out of range. 58 Pass Key fuel enable was not correct. (Eldorado & Seville only) 59 Transmission temperature was either above 335? F or below 104? F. 60 Transmission was not in drive when cruise control was engaged. 63 Vehicle speed was 20 MPH higher than the set speed for 0.5 seconds with cruise control on. 64 Vehicle speed increased more than 16 MPH (6 MPH on Eldorado & Seville) in 1 second while cruise control was engaged. 65 Coolant temperature was above 289? F when cruise control was engaged. 66 Engine RPM was 4800 or more for 0.25 seconds with cruise control engaged. 67 Cruise control Set/Coast or Resume/Accel signal was present when the cruise ON/OFF switch was turned on or Set/Coast and Resume/Accel signals were present at the same time. GM
88-90 3.8L VIN C

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds at normal engine temperature. 14 Coolant temperature sensor signal indicates a temperature of over 282? F for 0.4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -40? F for at least 2 seconds. 16 Charging system voltage was above 16 volts. 21 TPS voltage was above 2.5 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec. 22 TPS voltage was under 0.2 volts for 4 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature of 40? F for 4 seconds. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds when vehicle was in 4th gear. 25 Manifold air temperature sensor signal showed an air temperature over 283? F for 16 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 27 2nd gear switch was closed or grounded when vehicle was in 4th gear, or 2nd or 4th gear switch was open when engine was first started. 28 3rd gear switch was closed or grounded when vehicle was in 4th gear, or 3rd or 4th gear switch was open when engine was first started. 29 4th gear switch was closed or grounded when vehicle was in 4th gear, or 4th gear switch was open when engine was first started. 31 Park/Neutral switch was grounded when vehicle was in gear, or Park/Neutral switch was open when vehicle was first started, or the 4th gear switch has an intermittent open. 34 There was no MAF signal for over 4 seconds while engine was running. 38 Vehicle speed went from above 35 MPH to 0 several times without a brake input signal. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds in closed loop operation with a throttle angle between 0.54 and 2.08 volts after engine had been running for 1 minute. 46 Power steering switch was closed for 25 seconds or more when vehicle speed was above 40 MPH. 47 Momentary loss of power to Body Computer Module (BCM). 51 MEM-CAL error. 58 Security system pass key signal was out of range when the ignition was turned to On or Start position. 63 Incorrect EGR operation. 64 Incorrect EGR operation. 65 Incorrect EGR operation. GM
88-93 5.0L VIN E TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. On Brougham models the inlet air temperature sensor signal shows a temperature above 297? F with an engine speed greater than 35 MPH. 32 EGR open command did not change the MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 4 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation. On Brougham models the oxygen sensor voltage was under 0.2 volts. 45 Oxygen sensor voltage was over 0.75 volts for 30 seconds with a throttle angle above 20%. On Brougham models the oxygen sensor voltage was over 0.7 volts. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
89 2.0L VIN 1 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed loop operation after the engine had been running for 40 seconds and the throttle angle was above 7%. (For the Lumina the oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds after the engine had been running for 2 minutes). 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F for 60 seconds after the engine has been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -31? F after the engine has been running for 2 minutes. 24 When engine speed was between 1400 and 4400 RPM, the MAP sensor signal showed low voltage (High manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 275? F for more than 2 seconds after the engine has been running for 5 minutes and vehicle speed was greater than 44 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 20%. 35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over 0.750 volts for 50 seconds in a closed loop. Lumina was over 0.700 volts for 30 seconds and throttle angle was between 3% and 45%. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for more than 50 seconds. Repair charging system. GM
89 2.3L VIN A MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds at throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds after engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet Air Temperature Sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either below 1.25 volts or above 3.75 volts for 5 seconds, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle was in park or neutral at a speed less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear for 20 seconds. 65 Fuel injector driver current did not reach 4 amps. Injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. 66 A/C refrigerant pressure voltage was either less than 0.1 volts, or more than 4.9 volts for 5 seconds GM
89 3.1L VIN V MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds when the TPS signal was above 4%. The engine had been running for at least 2 minutes. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for at least 20 seconds. 21 TPS voltage was above 4.3 volts for 10 seconds when engine was running and air flow was less than 17 gm/sec. 22 TPS voltage was under 0.25 volts for 4 seconds when the ignition was on. 23 Manifold air temperature sensor signal showed an air temperature of -31? F for 10 seconds after engine had been running for 4 minutes. 24 Engine speed was between 2200 and 4400 RPM and transmission was not in park or neutral and TPS was less than 2% for 3 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293? F for 3 seconds when vehicle speed was greater than 3 MPH and engine had been running for 8 minutes. 26 Quad-driver sense voltage showed a low voltage when battery voltage should be present, or the sense voltage showed battery voltage when a low voltage should be present. 32 The ECM opens each EGR control valve during deceleration and monitors the change in manifold vacuum. The code is set when the change in manifold vacuum is outside the normal range. 33 MAP sensor voltage was too high for 4.8 seconds when throttle angle was less than 2%. 34 MAP sensor voltage was too low for 1 second when engine speed was under 600 RPM, or MAP sensor voltage was too low for 1 second when engine speed was over 600 RPM and throttle angle was above 20%. 41 Faulty or incorrect MEM-CAL. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for at least 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds in closed loop operation with a throttle angle between 3% and 45%. 51 MEM-CAL error. 52 CALPAK error. 53 ECM sees a battery voltage of more than 17.1 volts for 2 seconds. 54 Fuel pump voltage was less than 4 volts for 0.4 seconds. 62 Vehicle gear commanded by ECM did not match actual gear selected. 66 A/C pressure sensor voltage was either above 4.9 volts or below 0.1 volts for at least 5 seconds GM
89 5.7L VIN 8

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 seconds after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 3 seconds. 21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.5 volts at any time. 22 TPS voltage was under 0.2 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F for 12 seconds after I the engine has been running for 5 minutes. 24 Vehicle was not in park or neutral while engine speed was between 900 and 4400 RPM for 2 seconds with throttle closed. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 12 seconds after the engine has been running for 4 minutes and vehicle speed was above 5 MPH. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 1 second when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 600 RPM or the engine speed was over 600 RPM with a throttle position angle above 6%. 36 MAF sensor burn-off voltage was missing. Check MAF sensor burn-off relay and terminal "D" on MAF. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 43 The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle above 2%. The engine was running for at least 1 minute. 46 ECM did not receive the proper signal from vehicle anti-theft system when ignition was turned on. 51 MEM-CAL error. 52 CALPAK error. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received GM
89-90 5.7L VIN 7 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 52 CALPAK error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
88-90 5.7L VIN K

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 Vehicle Speed Sensor (VSS) Circuit . 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 35 Idle Air Control (IAC) System . 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. Electronic Spark Control (ESC) Circuit . 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. (Lean Exhaust Indicated) 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%.(Rich Exhaust Indicated) 51 PROM error. (MEM-CAL) 52 CALPAK error.Fuel CALPAK Missing . 53 System Over Voltage . 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command.(Low Voltage) 55 ECM error. Replace ECM.Faulty ECM GM
89-91 2.5L VIN R TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed loop operation after the engine had been running for 40 seconds and the throttle angle was above 7%. (For the Lumina the oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds after the engine had been running for 2 minutes). 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F for 60 seconds after the engine has been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -31? F after the engine has been running for 2 minutes. 24 When engine speed was between 1400 and 4400 RPM, the MAP sensor signal showed low voltage (High manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 275? F for more than 2 seconds after the engine has been running for 5 minutes and vehicle speed was greater than 44 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 20%. 35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts for 30 seconds and throttle angle was between 3% and 45%. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for more than 50 seconds. Repair charging system GM
89-91 3.3L VIN N MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds with a throttle angle above 4% after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 284? F for 4 seconds after engine had been running for 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 4 seconds with the l engine running. 16 ECM sees a battery voltage above 16 volts for more than 10 seconds. 21 TPS voltage was above 1.95 volts for 5 seconds when the MAP sensor signal showed a high manifold vacuum or the TPS was above 4.9 volts at any time. 22 TPS voltage was under 0.24 volts for 4 seconds when ignition was on. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds with engine running and transmission in high gear. 26 Quad-driver sense voltage shows a low voltage when battery voltage should be present or if the sense voltage shows battery voltage when a low voltage should be present. 27 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 3rd gear, or drive gear was open when engine was first started. 28 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 3rd gear, or drive gear was open when the engine was first started. 29 4th gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or drive gear was open when the engine was first started. 31 Park/Neutral switch was open for 4 consecutive starts, or Park/Neutral switch was grounded with transmission in high gear and vehicle speed was above 45 MPH for 12 seconds. 34 MAF sensor did not give any signal for 4 seconds when engine was running. 38 Brake switch signal was not present when vehicle speed changed from above 35 MPH to 0 MPH 23 or more times. 39 TCC was commanded by the ECM when transaxle was in high gear for 15 seconds but engine speed did not indicate that the TCC was engaged. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either above 3.5 volts or below 1.5 volts for 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 2 minutes of closed loop operation after engine had been running for at least 1 minute. 46 Power steering switch was closed while vehicle speed was over 40 MPH for more than 25 seconds. 48 Vehicle misfired. TPS was between 0.58 and 0.93 volts, engine RPM was between 1500 and 2500 and vehicle speed was between 50 and 60 MPH for 30 seconds. 66 A/C pressure sensor voltage was either above 4.9 volts or below 0.1 volt for 25 seconds GM
90 2.3L VIN D MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds at throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds after engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied by-pass voltage to the ignition module. 43 Knock sensor voltage was either below 1.25 volts or above 3.75 volts for 5 seconds, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle was in park or neutral at a speed less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear for 20 seconds. 65 Fuel injector driver current did not reach 4 amps, injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. 66 A/C refrigerant pressure voltage was either less than 0.1 volts, or more than 4.9 volts for 5 seconds GM
90 2.3L VIN A MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds at throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds after engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either below 1.25 volts or above 3.75 volts for 5 seconds, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle was in park or neutral at a speed less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear for 20 seconds. 65 Fuel injector driver current did not reach 4 amps. Injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. 66 A/C refrigerant pressure voltage was either less than 0.1 volts, or more than 4.9 volts for 5 seconds GM
90 3.8L VIN L

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110? F. 14 Coolant temperature sensor signal indicates a temperature of over 284? F for 0.4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36? F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was above 16 volts for 10 seconds. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.2 volts for 4 seconds when the ignition was on. On Bonneville, Le Sabre and Park Avenue the TPS voltage was between 0.48 and 1.3 volts for 30 seconds with engine speed between 1300 and 2100 RPM and vehicle speed between 50 and 60 MPH. 23 Inlet air temperature sensor signal showed an air temperature of -40? F for 0.4 seconds (On Regal the temperature was -31? F). 24 Vehicle speed sensor signal showed less than 3 MPH for 2 seconds when engine speed was greater than 3000 RPM and transmission has not been in park or neutral for more than 4 seconds. Or vehicle speed goes from above 18 MPH to 0 in less than 2 seconds without applying brake. 25 Inlet air temperature sensor signal showed an air temperature of over 218? F for 5 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 27 2nd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 2nd or 4th, gear switch was open when engine was first started. 28 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 3rd or 4th, gear switch was open when engine was first started. 29 4th gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 4th gear switch was open when engine was first started. 31 PRNDL indicates a gear other than park or neutral for 13 seconds for 3 consecutive startups when ignition was on, engine was off and vehicle speed was 0. Or the PRNDL status indicators (A, B, C, P) showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 38 Vehicle went from 35 MPH (for 10 seconds) to 0 MPH 5 times without a TCC brake input signal. 39 The Torque Converter Clutch portion of the brake switch was inoperative for 30 seconds causing vehicle speed ratio to be outside of its window of operation. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 51 MEM-CAL error. 63 EGR flow was incorrect. 64 EGR flow was incorrect. 65 EGR flow was incorrect. GM
90 4.5L VIN 3

12 PCM did not receive distributor reference pulses for 4 seconds while cam pulses were being received. 13 Right oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 311? F. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F. 16 Ignition voltage was either less than 10 volts or greater than 16 volts for 5 seconds. 17 Left oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature at a speed over 800 RPM. 19 Fuel pump feedback voltage stayed above 7 volts for 4 seconds after ignition was turned on. 20 Fuel pump feedback voltage was 2 volts or less for 1 second. 21 TPS value was 72 degrees or more for 0.7 seconds. 22 TPS value was 1.3 degrees or less for 0.7 seconds when the engine was running at 600 RPM or more. 23 EST signal did not change when the ECM applied bypass voltage to the ignition module. 24 Vehicle speed was 0 for 3 seconds with transmission in drive or reverse and brake off when throttle angle was at least 17 degrees and engine RPM was 1400 or greater. 26 Throttle switch input to the PCM was closed for 1.8 seconds while the TPS was between 20 and 75 degrees. 27 Throttle switch on the ISC motor never closed during idle operation. 28 3rd or 4th gear pressure switch was open when vehicle was stopped and transmission was in park or neutral. 30 TPS was 14 degrees or more while ISC was retracting for 15 seconds, or TPS was 2 degrees while ISC was extending for 15 seconds. 31 MAP sensor was shorted to 5 volts for 0.2 seconds. 32 MAP sensor was open showing a reading of 0.5 volts or less for 0.2 seconds. 34 MAP sensor signal voltage was too high (low vacuum) for 15 seconds when throttle switch was closed. 37 MAT sensor was shorted showing a temperature of 313? F or more. 38 MAT sensor was open showing a temperature of -27? F or less. 39 Engine RPM was outside of the range expected for indicated vehicle speed for 5 seconds indicating a VCC engagement problem. 40 Power steering switch was open when vehicle speed was 45 MPH or more. 41 Cam reference pulses were not received when distributor reference pulses were received for 5 seconds at an engine speed of 1600 RPM or less. 42 Left oxygen sensor was lean for more than 50 seconds when engine was at normal temperature with an engine speed of 800 RPM or more. 43 Left oxygen sensor was rich for more than 50 seconds when engine was at normal temperature with an engine speed of 800 RPM or more. 44 Right oxygen sensor was lean for more than 50 seconds when engine was at normal temperature with an engine speed of 800 RPM or more. 45 Right oxygen sensor was rich for more than 50 seconds when engine was at normal temperature with an engine speed of 800 RPM or more. 46 Left and right fuel control block learn value differed by more than 15 counts for 10 minutes. 47 ECM has received bad data from BCM for 3 seconds while engine speed was 500 RPM or more for 5 seconds. 48 EGR system fault. Oxygen sensor did not indicate a leaner mixture for at least 3 of 5 tests. 49 The oxygen sensor did not show excess oxygen when the air injection system sent air to the exhaust manifold (system had failed 4 times). 51 MEM-CAL error. 52 ECM has lost primary battery power. 53 Distributor reference pulses were not received for 0.4 seconds when engine speed was above 568 RPM. 55 TPS zero point was out of range. 58 Pass Key fuel enable was not correct. 60 Transmission was not in drive when cruise control was engaged. 61 Cruise vent solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. 62 Cruise vacuum solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. 63 Vehicle speed was 20 MPH higher than the set speed for 0.5 seconds when cruise control was on. 64 Vehicle speed increased more than 16 MPH in 1 second while cruise control was engaged. 65 Cruise control servo position was 6.3% or less for 1 second. 66 Engine RPM was 4800 or more for 0.25 seconds with cruise control engaged. 67 Cruise control Set/Coast or Resume/Accel switch was closed for 10 minutes. 68 With cruise control engaged the throttle angle was greater than 20 degrees and servo position sensor indicated a stroke greater than commanded for 2 seconds. 74 MAT sensor signal changed 0.3 volts or more in 0.25 seconds. 75 Vehicle speed changed by 8 MPH or more in 1 second while MAP sensor remained steady with engine running and brakes not applied. 85 The coast down throttle angle offset is more than 5 degrees from the zero value. 90 Park/neutral switch was closed when 4th gear switch was open and vehicle speed was between 23 and 35 MPH for 10 seconds. 91 Gear selector switch has either an open or a short causing an invalid signal for a forward or reverse gear. 96 Throttle angle was 65 degrees or more for 12 seconds with transmission in drive or reverse and vehicle speed was 5 MPH or less with brake being applied. 97 Gear selector was moved from park or neutral to drive or reverse with engine speed over 2000 RPM but under 6 MPH. 98 At a vehicle speed under 6 MPH, the gear selector was moved from park or neutral into drive or reverse when engine speed was 600 RPM greater than determined by PCM and throttle angle was 20 degrees or less. 99 Servo position sensor indicated that servo was still engaged after cruise control had been disengaged for 2 seconds. Throttle angle was above 20 degrees. GM
90 5.7L VIN J

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F. 15 Coolant temperature sensor signal indicates a temperature colder than -26? F. 16 DIS fault line voltage was low for 2 seconds when EST was disabled. 21 TPS voltage was above 2.5 volts for 2 seconds when the engine was running, or when the TPS was above 4.92 volts at any time. 22 TPS voltage was under 0.24 volts when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F for 1 second after the engine has been running for 2 minutes. 24 Vehicle speed was 0 MPH when engine speed was between 900 and 4400 RPM and throttle position angle was less than 2% for 4 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 3 seconds after the engine has been running for 2 minutes. 31 Cam pulse was missing on the first pass through the internal ECM self test of the cam sensor, or for any 3-minute period. 33 MAP sensor signal voltage was too high (low vacuum) for 0.5 seconds when throttle opening was under 3%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 700 RPM, or when TPS was greater than 20% with an engine speed above 700 RPM. 36 The DIS module did not sense the correct EST signal from ECM for 10 consecutive attempts. 42 The EST signal was not received by ECM for 0.5 seconds when EST mode was enabled or when bypass mode was enabled. 43 One or both of the knock sensors were either open or grounded for 5 seconds. 44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Left oxygen sensor voltage was over 0.75 volts for 30 seconds when the throttle angle was above 4% during closed loop operation. 46 ECM did not receive the proper signal from vehicle anti-theft system when ignition was turned on. 52 Engine oil temperature was below -36? F after engine had been running for 30 minutes. 53 ECM detected a battery voltage either above 17.1 volts or below 8 volts. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received. 55 ECM detected a lean oxygen sensor voltage for 2 seconds during the power enrichment modes of operation. 56 Vacuum sensor voltage was either above 5 volts or below 0.46 volts. 61 Vacuum sensor voltage was between 0.76 and 4.89 volts when secondary port throttle valves were commanded closed, or the vacuum sensor voltage was below 1.7 volts when the secondary port throttle valves were commanded open. 62 Engine oil temperature sensor showed oil temperature above 284? F after the engine had been running at least 30 minutes. 63 Right oxygen sensor was open showing a steady voltage between 0.35 and 0.55 volts for 60 seconds after the engine had been running for at least 2 minutes. 64 Right oxygen sensor voltage was below 0.2 volts for 50 seconds of closed loop operation. 65 Right oxygen sensor voltage was above 0.75 volts for 30 seconds of closed loop operation when the throttle angle was above 20% or below 2.7% GM
90-91 2.2L VIN G TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds. Engine was at normal operating temperature and had been running for at least 40 seconds after start with a throttle angle above 7%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more with an engine speed less than 1800 RPM. 22 TPS voltage was under 0.2 volts when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -31? F after the engine has been running for 2 minutes (on Beretta & Corsica, engine has been running for 9 minutes). 24 When engine speed was between 1200 and 4400 RPM, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 275? F for more than 2 seconds after the engine had been running for 9 minutes. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was above 1200 RPM and TPS was greater than 20%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds or more in closed loop operation. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for 10 seconds. Repair charging system. GM
90-91 3.1L VIN V MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds when the TPS signal was above 4%. The engine had been running for at least 2 minutes. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for at least 20 seconds. 21 TPS voltage was above 4.3 volts for 10 seconds when engine was running and air flow was less than 17 gm/sec. 22 TPS voltage was under 0.25 volts for 4 seconds when the ignition was on. 23 Manifold air temperature sensor signal showed an air temperature of -31? F for 10 seconds after engine had been running for 4 minutes. 24 Engine speed was between 2200 and 4400 RPM and transmission was not in park or neutral and TPS was less than 2% for 3 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 293? F for 3 seconds when vehicle speed was greater than 3 MPH and engine had been running for 8 minutes. 26 Quad-driver sense voltage showed a low voltage when battery voltage should be present, or the sense voltage showed battery voltage when a low voltage should be present. 32 The ECM opens each EGR control valve during deceleration and monitors the change in manifold vacuum. The code sets when the change in manifold vacuum is outside the normal range. 33 MAP sensor voltage was too high for 4.8 seconds when throttle angle was less than 2%. 34 MAP sensor voltage was too low for 1 second when engine speed was under 600 RPM, or MAP sensor voltage was too low for 1 second when engine speed was over 600 RPM and throttle angle was above 20%. 35 Engine idle speed is either 300 RPM above or below the desired idle speed for 50 seconds. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for at least 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds in closed loop operation with a throttle angle between 3% and 45%. 51 MEM-CAL error. 52 CALPAK error. 53 ECM sees a battery voltage of more than 17.1 volts for 2 seconds. 54 Fuel pump voltage was less than 4 volts for 0.4 seconds. 62 Vehicle gear commanded by ECM did not match actual gear selected. 66 A/C pressure sensor voltage was either above 4.9 volts or below 0.1 volts for at least 5 seconds GM
90-91 5.0L VIN F

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 3 seconds. 21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.8 volts at anytime. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below 22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1400 and 3600 RPM and throttle position angle was less than 2% for at least 4 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 2 seconds after the engine has been running for 2 minutes and vehicle speed was greater than 5 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor voltage was too low (high vacuum) when engine speed was over 1200 RPM, or when TPS was over 21% when engine speed was over 1200 RPM. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was above 3.5 volts or below 1.5 volts for 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds with a throttle angle above 2%. 51 MEM-CAL error. 52 CALPAK error. 53 ECM sees a battery voltage of more than 17.1 volts for 2 seconds. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received GM
90-91 5.7L VIN 8

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 seconds after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 3 seconds. 21 TPS voltage was above 2.5 volts for 3 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or TPS was above 4.5 volts at any time. 22 TPS voltage was under 0.2 volts for 3 seconds when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F for 12 seconds after the engine has been running for 5 minutes. 24 Vehicle speed was 0 MPH when engine speed was between 900 and 3000 RPM and throttle position angle was less than 2% for at least 4 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 12 seconds after the engine has been running for 4 minutes and vehicle speed was above 5 MPH. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 1 second when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 600 RPM or the engine speed was over 600 RPM with a throttle position angle above 6%. 41 Faulty or incorrect MEM-CAL. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle above 2%. The engine was running for at least 1 minute. 46 ECM did not receive the proper signal from vehicle anti-theft system when ignition was turned on. 51 MEM-CAL error. 52 Engine oil temperature was below -31? F after the engine had been running for 30 minutes. 53 ECM sees a battery voltage either above 17.1 volts or below 8.0 volts. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received. 62 Engine oil temperature was above 284? F after engine had been running for 30 minutes. GM
91 2.3L VIN D MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds at throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds after engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15" or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet air temperature sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either below 1.25 volts or above 3.75 volts for 5 seconds, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle was in park or neutral at a speed less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear for 20 seconds. 65 Fuel injector driver current did not reach 4 amps. Injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. 66 A/C refrigerant pressure voltage was either less than 0.1 volts, or more than 4.9 volts for 5 seconds GM
91 2.3L VIN A MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds at throttle angle above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds after engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after engine had been running for 50 seconds. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either below 1.25 volts or above 3.75 volts for 5 seconds, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle was in park or neutral at a speed less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear for 20 seconds. 65 Fuel injector driver current did not reach 4 amps. Injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. 66 A/C refrigerant pressure voltage was either less than 0.1 volts, or more than 4.9 volts for 5 seconds. GM
91 3.8L VIN C

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110? F. 14 Coolant temperature sensor signal indicates a temperature of over 284? F for 0.4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36? F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was either below 9 volts or above 17 volts for 10 seconds. 17 PCM did not detect any spark reference pulses within 240 fuel control reference pulses (80 crank revolutions) while engine was running below 1200 RPM. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.2 volts for 4 seconds when the ignition was on. 23 Inlet air temperature sensor signal showed an air temperature of -29? F for 4 seconds. 24 Vehicle speed sensor signal showed less than 3 MPH for 2 seconds when engine speed was greater than 3000 RPM and transmission has not been in park or neutral for more than 4 seconds. Or vehicle speed goes from above 18 MPH to 0 in less than 2 seconds without applying brake. 25 Inlet air temperature sensor signal showed an air temperature over 218? F for 5 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 31 PRNDL indicates a gear other than park or neutral for 0.13 seconds for 3 consecutive startups when ignition was on, engine was off and vehicle speed was 0. Or the PRNDL status indicators (A, B, C, P) showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 36 Transmission solenoid "B" has failed in the Off position which caused transmission to be in 3rd j when 1st gear was desired, or solenoid "B" failed in the On position which caused transmission to be in 1st when 3rd gear was desired. 38 Vehicle speed went from 35 MPH or more (for 10 seconds) and back to 0 MPH 5 times without a brake input signal. 41 Cam sensor signal was not received by PCM for the last 5 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 47 Momentary loss of power to Body Computer Module (BCM). 51 MEM-CAL error. 58 Security system pass key signal was out of range when the ignition was turned to On or Start position. 61 Cruise vent solenoid was shorted, grounded, or open for 1/2 second or longer. 62 Cruise VAC solenoid was shorted, grounded, or open for 1/2 second or longer. 65 Cruise servo position sensor was shorted, grounded, or open. 67 Cruise switch was open between Cruise Engage and the PCM, or the Set/Coast switch was closed for too long, or the Resume/Accel switch was closed for too long, or the Cruise switch was open between the PCM and Brake switch after the vehicle had made 5 stops of 10 seconds or longer, or any of the cruise switches have been shorted to voltage. 68 Servo Position sensor from the PCM to the cruise servo had a position above 12% for 1 1/2 seconds. GM
91 3.8L VIN L

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110? F. 14 Coolant temperature sensor signal indicates a temperature of over 284? F for 0.4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36? F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was above 17 volts or below 9 volts for 10 seconds. 17 ECM detected incorrect number of spark reference pulses to fuel control reference pulses for 80 crank revolutions. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.2 volts for 4 seconds when the ignition was on. On Bonneville, Le Sabre, and Park Avenue the TPS voltage was between 0.48 and 1.3 volts for 30 seconds with engine speed between 1300 and 2100 RPM and vehicle speed between 50 and 60 MPH. 23 Inlet air temperature sensor signal showed an air temperature of 40? F for 0.4 seconds (On Regal the temperature was -31? F). 24 Vehicle speed sensor signal showed less than 3 MPH for 2 seconds when engine speed was greater than 3000 RPM and transmission has not been in park or neutral for more than 4 seconds. Or vehicle speed goes from above 18 MPH to 0 in less than 2 seconds without applying brake. 25 Inlet air temperature sensor signal showed an air temperature of over 218? F for 5 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 27 2nd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 2nd or 4th gear switch was open when engine was first started. 28 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 3rd or 4th gear switch was open when engine was first started. 29 4th gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 4th gear switch was open when engine was first started. 31 PRNDL indicates a gear other than park or neutral for 13 seconds for 3 consecutive startups when ignition was on, engine was off and vehicle speed was 0. Or the PRNDL status indicators (A, B, C, P) showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 36 Transmission solenoid "B" has failed in the Off position which caused transmission to be in 4th when 1st gear was desired, or solenoid "B" failed in the On position which caused transmission to be in 1st when 4th gear was desired. 38 Vehicle went from 35 MPH (for 10 seconds) to 0 MPH 5 times without a TCC brake input signal. 39 The Torque Converter Clutch portion of the brake switch was inoperative for 30 seconds causing vehicle speed ratio to be outside of its window of operation. 41 Cam sensor signal was not received by PCM for the last 2 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 47 Momentary loss of power to Body Computer Module (BCM). 51 MEM-CAL error. 58 Security system pass key signal was out of range when the ignition was turned to On or Start position. 61 Cruise vent solenoid was shorted, grounded, or open for 1/2 second or longer. 62 Cruise VAC solenoid was shorted, grounded, or open for 1/2 second or longer. 63 EGR flow was incorrect. EGR solenoid did not work properly. 64 EGR flow was incorrect. EGR solenoid did not work properly. 65 Cruise servo position sensor was shorted, grounded, or open. 66 A/C compressor signal lasted less than 1.5 seconds for 10 consecutive cycles. 67 Cruise switch was open between Cruise Engage and the PCM, or the Set/Coast switch was closed for too long, or the Resume/Accel switch was closed for too long, or the Cruise switch was open between the PCM and Brake switch after the vehicle had made 5 stops of 10 seconds or longer, or any of the cruise switches have been shorted to voltage. 68 Servo Position sensor from the PCM to the cruise servo had a position above 12% for 1 1/2 seconds. 69 A/C head pressure switch circuit was shorted for the first 5 seconds of engine run time. GM
91 4.9L VIN B

12 PCM did not receive distributor reference pulses for 4 seconds. 13 Oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature at a speed over 800 RPM. 14 Coolant temperature sensor signal indicates a temperature of over 311? F. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F. 16 Ignition voltage was either less than 10 volts or greater than 16 volts for 5 seconds. 19 Fuel pump feedback voltage stayed above 7 volts for 4 seconds after ignition was turned on. 20 Fuel pump feedback voltage was 2 volts or less for 1 second. 21 TPS value was 72 degrees or more for 0.7 seconds. 22 TPS value was 1.3 degrees or less for 0.7 seconds when the engine was running at 600 RPM or more. 23 EST signal did not change when the ECM applied bypass voltage to the ignition module. 24 Vehicle speed was 0 for 3 seconds with transmission in drive or reverse and brake off when throttle angle was at least 17 degrees and engine RPM was 1400 or greater. 26 Throttle switch input to the PCM was closed for 1.8 seconds while the TPS was between 20 and 75 degrees. 27 Throttle switch on the ISC motor never closed during idle operation. 30 TPS was 14 degrees or more while ISC was retracting for 15 seconds, or TPS was 2 degrees while ISC was extending for 15 seconds. 31 MAP sensor was shorted to 5 volts for 0.2 seconds. 32 MAP sensor was open showing a reading of 0.5 volts or less for 0.2 seconds. 34 MAP sensor signal voltage was too high (low vacuum) for 15 seconds when throttle switch was closed. 37 MAT sensor was shorted showing a temperature of 313? F or more. 38 MAT sensor was open showing a temperature of -27? F or less. 39 Engine RPM was outside of the range expected for indicated vehicle speed indicating a VCC engagement problem. 40 Power steering switch was open when vehicle speed was 45 MPH or more. 41 CAM reference pulses were not received when distributor reference pulses were received for 5 seconds at an engine speed of 1600 RPM or less. 44 Oxygen sensor was lean for more than 50 seconds. 45 Oxygen sensor was rich for more than 50 seconds. 47 ECM has received bad data from BCM for 5 seconds while engine speed was 500 RPM or more. 48 EGR open command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. Vehicle speed was over 35 MPH and engine was warm. 52 ECM has lost primary battery power. 53 Distributor reference pulses were not received for 0.4 seconds. 55 TPS zero point was out of range. 58 Pass Key fuel enable was not correct. 60 Transmission was not in drive when cruise control was engaged. 61 Cruise vent solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. 62 Cruise vacuum solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. 63 Vehicle speed was 20 MPH higher than the set speed for 0.5 seconds when cruise control was on. 64 Vehicle speed increased more than 16 MPH in 1 second while cruise control was engaged. 65 Cruise control servo position was 6.3% or less for 1 second. 66 Engine RPM was 4800 or more for 0.25 seconds with cruise control engaged. 67 Cruise control Set/Coast or Resume/Accel switch was closed for 10 minutes. 68 With cruise control engaged the throttle angle was greater than 20 degrees and servo position sensor indicated a stroke greater than commanded for 2 seconds. 70 Throttle position changed too rapidly without a corresponding change in MAP sensor signal when engine was running. 71 MAP sensor signal changed too rapidly while TPS signal was steady and engine speed did not change. 73 Coolant temperature sensor voltage has changed 0.3 volts in 1 second. 74 MAT sensor signal changed 0.3 volts or more in 0.25 seconds. 75 Vehicle speed changed by 8 MPH or more in 1 second while MAP sensor remained steady with engine running and brakes not applied. 80 Block learn was 104 or less for 25 seconds with a throttle angle between 6 degrees and 30 degrees and engine was warm. 85 The coast down throttle angle offset is more than 5 degrees from the zero value. 90 Vehicle speed cycles from 30 MPH to 0 at least 10 consecutive times with no VCC brake switch input. 91 Gear selector switch has either an open or a short causing an invalid signal for a forward or reverse gear. 92 Heated window signal was present at PCM for 10 minutes or more. 96 Throttle angle was 65 degrees or more for 12 seconds with transmission in drive or reverse and vehicle speed was 5 MPH or less with brake being applied. 97 Gear selector was moved from park or neutral to drive or reverse with engine speed over 2000 RPM but under 6 MPH. 98 At a vehicle speed under 6 MPH, the gear selector was moved from park or neutral into drive or reverse when engine speed was 600 RPM greater than determined by PCM. 99 Servo position sensor indicated that servo was still engaged after cruise control had been disengaged for 2 seconds. Throttle angle was above 20 degrees. GM
91 5.7L VIN 7 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 2%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. On Fleetwood the inlet air temperature signal shows a temperature above 297? F for 5 seconds at a speed less than 35 MPH. 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or the engine speed was over 1200 RPM with a throttle position angle above 21%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 30 seconds of closed loop operation with a throttle angle between 2% and 20%. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
91 5.7L VIN J

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F. 15 Coolant temperature sensor signal indicates a temperature colder than -26? F. 16 DIS fault line voltage was low for 2 seconds when EST was disabled. 21 TPS voltage was above 2.5 volts for 2 seconds when the engine was running, or when the TPS was above 4.92 volts at any time. 22 TPS was under 0.24 volts when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F for 1 second after the engine has been running for 2 minutes. 24 Vehicle speed was 0 MPH when engine speed was between 900 and 4400 RPM and throttle position angle was less than 2% for 4 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 3 seconds after the engine has been running for 2 minutes. 31 Cam pulse was missing on the first pass through the internal ECM self test of the cam sensor, or for any 3-minute period. 33 MAP sensor signal voltage was too high (low vacuum) for 0.5 seconds when throttle opening was under 3%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 700 RPM, or when TPS was greater than 20% with an engine speed above 700 RPM. 36 The DIS module did not sense the correct EST signal from ECM for 10 consecutive attempts. 42 The EST signal was not received by ECM for 0.5 seconds when EST mode was enabled or when bypass mode was enabled. 43 Knock sensor signal was not received by ECM for 4 seconds when engine was running. 44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Left oxygen sensor voltage was over 0.75 volts for 30 seconds when the throttle angle was above 4% during closed loop operation. 46 ECM did not receive the proper signal from vehicle anti-theft system when ignition was turned on. 52 Engine oil temperature was below -36? F after engine had been running for 30 minutes. 53 ECM detected a battery voltage either above 17.1 volts or below 8 volts. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received. 55 ECM detected a lean oxygen sensor voltage for 2 seconds during the power enrichment modes of operation. 56 Vacuum sensor voltage was either above 5 volts or below 0.46 volts. 61 Vacuum sensor voltage was between 0.76 and 4.89 volts when secondary port throttle valves were commanded closed, or the vacuum sensor voltage was below 1.7 volts when the secondary port throttle valves were commanded open. 62 Engine oil temperature sensor showed an oil temperature above 284? F after the engine had been running at least 30 minutes. 63 Right oxygen sensor was open showing a steady voltage between 0.35 and 0.55 volts for 60 seconds after the engine had been running for at least 2 minutes. 64 Right oxygen sensor voltage was below 0.2 volts for 50 seconds of closed loop operation. 65 Right oxygen sensor voltage was above 0.75 volts for 30 seconds of closed loop operation when the throttle angle was above 20% or below 2.7% GM
91-92 1.9L VIN 9 TBI

11 Transaxle trouble code is present. 12 PCM self-diagnostic test is OK. 13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 20 seconds when the engine was at normal operating temperature. 14 Coolant temperature sensor signal indicates a temperature of over 284? F. 15 Coolant temperature sensor signal indicates a temperature colder than -31? F. 16 PCM desired current did not match with feedback current. 17 Coolant temperature signal did not change when PCM pull-up resistor switched. 19 Crankshaft position signal (6X) did not occur between each reference pulse for 3 consecutive times. 21 TPS voltage was above 4.9 volts. 22 TPS voltage was under 0.2 volts. 23 Inlet air temperature sensor signal showed an air temperature of -22? F. 24 Vehicle speed sensor signal showed less than 1 MPH when engine speed was above idle and transmission was not in park or neutral. 25 Inlet air temperature sensor signal showed an air temperature over 257? F. 26 Any of the quad-driver module circuits had an open or short for 25 seconds. 27 Any of the quad-driver module circuits had an open or short for 5 seconds. 32 EGR system fault. Fuel mixture did not change when EGR solenoid was commanded ON and OFF. 33 MAP sensor signal voltage was greater than 4.2 volts when throttle angle was less than 5%. 34 MAP sensor signal voltage was less than 2 volts when engine speed was less than 1200 RPM. 35 Idle speed was either above or below desired idle. 41 Electronic ignition circuit was either open or grounded. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ESC circuit voltage was out of range for 10 seconds. 44 Oxygen sensor voltage was under 0.3 volts for 3 minutes of closed loop operation. 48 PCM detected extra or missing crank reference pulses. 49 IAC was working improperly. Engine idle RPM was too high. 51 PROM error. 52 PCM sees a battery voltage either above 17 volts or below 11 volts. 53 Knock sensor could not eliminate engine noise by retarding timing. 54 Either the MAP sensor, Handwheel sensor, TPS, or all three sensors were grounded to 0 volts. 55 Analog to digital signal conversion was incorrect. 58 Battery voltage has changed more than 3 volts instantly. 63 Option check-sum error. Invalid combinations of tire sizes or other options. 67 Handwheel sensor voltage was either above 4.8 volts or below 0.2 volts. 71 Engine coolant temperature was above 244? F. 72 Engine coolant temperature was below 32? F after engine had been running for 5 minutes. 73 Engine coolant temperature changed more than 59? F in 0.1 second. 74 Engine coolant temperature sensor reading was less than the transaxle temperature sensor reading. 75 Inlet air temperature reading changed more than 59? F in 0.1 second. 76 MAP sensor signal did not change with a corresponding change in the TPS. 82 PCM is out of calibration. Recalibrate PCM. If code 82 still exists then replace PCM. 84 Communications error between engine control module and transaxle controller. GM
91-92 1.9L VIN 7 SPFI

11 Transaxle trouble code is present. 12 PCM self-diagnostic test is OK. 13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 20 seconds when the engine was at normal operating temperature. 14 Coolant temperature sensor signal indicates a temperature of over 284? F. 15 Coolant temperature sensor signal indicates a temperature colder than -31? F. 16 PCM desired current did not match with feedback current. 17 Coolant temperature signal did not change when PCM pull-up resistor switched. 19 Crankshaft position signal (6X) did not occur between each reference pulse for 3 consecutive times. 21 TPS voltage was above 4.9 volts. 22 TPS voltage was under 0.2 volts. 23 Inlet air temperature sensor signal showed an air temperature of -22? F. 24 Vehicle speed sensor signal showed less than 1 MPH when engine speed was above idle and transmission was not in park or neutral. 25 Inlet air temperature sensor signal showed an air temperature over 257? F. 26 Any of the quad-driver module circuits had an open or short for 25 seconds. 27 Any of the quad-driver module circuits had an open or short for 5 seconds. 32 EGR system fault. Fuel mixture did not change when EGR solenoid was commanded ON and OFF. 33 MAP sensor signal voltage was greater than 4.2 volts when throttle angle was less than 5%. 34 MAP sensor signal voltage was less than 2 volts when engine speed was less than 1200 RPM. 35 Idle speed was either above or below desired idle. 41 Electronic ignition circuit was either open or grounded. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ESC circuit voltage was out of range for 10 seconds. 44 Oxygen sensor voltage was under 0.3 volts for 3 minutes of closed loop operation. 48 PCM detected extra or missing crank reference pulses. 49 IAC was working improperly. Engine idle RPM was too high. 51 PROM error. 52 PCM sees a battery voltage either above 17 volts or below 11 volts. 53 Knock sensor could not eliminate engine noise by retarding timing. 54 The MAP sensor, Handwheel sensor, TPS, or all three sensors were grounded to 0 volts. 55 Analog to digital signal conversion was incorrect. 58 Battery voltage has changed more than 3 volts instantly. 63 Option check-sum error. Invalid combinations of tire sizes or other options. 67 Handwheel sensor voltage was either above 4.8 volts or below 0.2 volts. 71 Engine coolant temperature was above 244? F. 72 Engine coolant temperature was below 32? F after engine had been running for 5 minutes. 73 Engine coolant temperature changed more than 59? F in 0.1 second. 74 Engine coolant temperature sensor reading was less than the transaxle temperature sensor reading. 75 Inlet air temperature reading changed more than 59? F in 0.1 second. 76 MAP sensor signal did not change with a corresponding change in the TPS. 82 PCM is out of calibration. Recalibrate PCM. If code 82 still exists then replace PCM. 84 Communications error between engine control module and transaxle controller GM
91-92 3.4L VIN X MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 25 seconds. The engine had been running for at least 2 minutes and the TPS was above 4%. 14 Coolant temperature sensor signal indicates a temperature of over 270? F after the engine had been running for 20 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -37? F when the engine was running. 21 TPS voltage was above 3.78 volts for 1.25 seconds. 22 TPS voltage was under 0.25 volts for 10 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -31? F for 10 seconds after the engine has been running for 4 minutes. 24 Vehicle speed sensor signal showed less than 2 MPH for 3 seconds when throttle position signal was less than 2% with engine speed between 2200 and 4400 RPM with the vehicle in gear. 25 Inlet air temperature sensor signal showed an air temperature of over 293? F and vehicle speed was greater than 1 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 6%. 34 MAP sensor signal voltage was too low (high vacuum) for 22 seconds when engine speed was under 625 RPM, or when engine speed was over 625 RPM and throttle opening was over 20% for 22 seconds. 35 Idle speed was over 200 RPM outside the desired engine speed commanded by the ECM for 50 seconds. 39 Transaxle clutch switch has failed 4 consecutive times. Vehicle was at normal operating temperature and the speed went from 0 to 40 MPH or more and back to 0 again. 41 MEM-CAL error. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal voltage was either above 4.8 volts or below 0.64 volts for 10 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds of closed loop operation. Engine had been running for at least 1 minute with the throttle angle between 3% and 45%. 51 PROM error. 55 ECM error. Replace ECM GM
92 2.0L VIN H MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds with engine running at normal temperature and throttle angle was above 6.5%. 14 Coolant temperature sensor signal indicates a temperature of above 289? F or under -30? F for 3 seconds after the engine has been running for 2 minutes. 15 ECM did not receive 58X (58 pulses per crank revolution) signal or the signal was incorrect for at least 10 seconds. 21 TPS voltage was above 2.5 volts or below 0.2 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 23 Inlet air temperature sensor signal showed an air temperature of less than 30? F or more than 302? F for 2 seconds after the engine has been running for 2 minutes. 24 Vehicle speed sensor signal showed less than 5 MPH. Vehicle was not in park or neutral and had an engine speed between 1400 and 3600 RPM and the MAP signal showed high manifold vacuum. 25 Manifold air temperature voltage indicated an air temperature above 275? F for 30 seconds. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 15%. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds after the engine had been running for at least 2 minutes with a throttle angle above 5%. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation after the engine had been running for at least 2 minutes with a throttle angle above 5%. 51 ECM error. 66 A/C pressure sensor signal voltage was outside of the normal possible range. GM
92 2.2L VIN 4

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 40 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature below -30? F or above 275? F for 3 seconds after the engine has been running for 2 minutes. 21 TPS voltage was above 3.9 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more and engine speed was less than 1750 RPM or TPS voltage was below 1.9 volts for 64 seconds. 23 Inlet air temperature sensor signal showed an air temperature below -30? F or above 302? F for more than 2 seconds after the engine has been running for 2 minutes. 24 When engine speed was between 1400 and 3600 RPM and the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was higher than 3.7 volts for 5 seconds when throttle opening was under 5%, or MAP sensor signal was lower than 0.3 volts when throttle opening was over 15%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for at least 50 seconds of closed loop operation. 51 ECM error. Check that all ECM connections are good and recheck ECM. If code 51 still exists then replace ECM. 66 A/C refrigerant pressure voltage was either less than 0.3 volts or greater than 4.9 volts for 5 seconds GM
92 2.3L VIN D MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 285? F after engine had been running for at least 2 minutes, or if coolant temperature sensor was shorted to ground. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 60 seconds. 16 ECM did not receive 2X pulses while receiving 1X pulses. 19 7X reference signal problem. ECM has detected either too many or too few pulses between sync signal within 4 minutes. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet air temperature sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8-2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.3 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 51 EPROM error. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle speed was less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear. 65 Fuel injector driver current did not reach 4 amps, injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. GM
92 2.3L VIN A MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 285? F after engine had been running for at least 2 minutes, or if coolant temperature sensor was shorted to ground. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 60 seconds. 16 ECM did not receive 2X pulses while receiving 1X pulses. 19 7X reference signal problem. ECM has detected either too many or too few pulses between sync signal within 4 minutes. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of 29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.3 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 51 EPROM error. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle speed was less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear. 65 Fuel injector driver current did not reach 4 amps. Injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. GM
92 2.3L VIN 3 MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 285? F after engine had been running for at least 2 minutes, or if coolant temperature sensor was shorted to ground. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 60 seconds. 16 ECM did not receive 2X pulses while receiving 1X pulses. 19 7X reference signal problem. ECM has detected either too many or too few pulses between sync signal within 4 minutes. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -29? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet air temperature sensor signal showed an air temperature over 318? F with a vehicle speed greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle, or the knock signal was present for 3.67 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.3 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 51 EPROM error. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds with ignition on. 62 Vehicle speed was less than 5 MPH when vehicle was in 2nd or 3rd gear, or vehicle speed was greater than 50 MPH when vehicle was in 1st or 2nd gear. 65 Fuel injector driver current did not reach 4 amps, injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. GM
92 2.5L VIN R TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds during closed loop operation and will set code after 40 seconds for Century and Cutlass Ciera. For the Lumina the oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds during closed loop operation and will set code after 2 minutes. Both systems can go into open loop after 15 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 3 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -22? F after the engine has been running for 2 minutes. 21 TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more under 1800 RPM. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet ATS signal showed an air temperature of -22? F after the engine has been running for 1 minute. 24 Throttle position signal was less than 2% with engine speed between 1400 and 4400 RPM and the MAP signal showed low voltage and high manifold vacuum. Transmission was not in park or neutral. 25 Inlet ATS signal showed an air temperature over 275? F for more than 2 seconds after the engine has been running for 5 minutes and vehicle speed was greater than 44 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds when throttle opening was under 2%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 20%. 35 Idle speed was over 150 RPM outside the desired engine speed commanded by the ECM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was above specification. Century and Cutlass Ciera was over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7 volts for 30 seconds and throttle angle was between 3% and 45%. 51 PROM error. 53 Charging system voltage was greater than 16.9 volts for more than 50 seconds. Repair charging system GM
92 5.0L VIN F

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start above 1600 RPM with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3% for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 70 seconds with a throttle angle between 2% and 20%. The engine had been running for at least 1 minute. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
92 5.7L VIN 7 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below 22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. On Brougham models the inlet air temperature sensor signal shows a temperature above 297? F with an engine speed greater than 35 MPH. 32 EGR open command did not change the MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 4 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation. On Brougham models the oxygen sensor voltage was under 0.2 volts. 45 Oxygen sensor voltage was over 0.75 volts for 30 seconds with a throttle angle above 20%. On Brougham models the oxygen sensor voltage was over 0.7 volts. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
92 5.7L VIN J

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F. 15 Coolant temperature sensor signal indicates a temperature colder than -26 F. 16 DIS fault line voltage was low for 2 seconds when EST was disabled. 21 TPS voltage was above 2.5 volts for 2 seconds when the engine was running, or when the TPS was above 4.8 volts at any time. 22 TPS voltage was under 0.23 volts when the engine was running. 23 Manifold air temperature sensor signal showed an air temperature below -22? F for 1 second after the engine has been running for 2 minutes. 24 Vehicle speed was 0 MPH when engine speed was between 900 and 4400 RPM and throttle position angle was less than 2% for 4 seconds. 25 Manifold air temperature sensor signal showed an air temperature over 302? F for 3 seconds after the engine has been running for 2 minutes. 31 Cam pulse was missing on the first pass through the internal ECM self test of the cam sensor, or for any 3-minute period. 33 MAP sensor signal voltage was too high (low vacuum) for 0.5 seconds when throttle opening was under 3%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 700 RPM, or when TPS was greater than 20% with an engine speed above 700 RPM. 36 The DIS module did not sense the correct EST signal from ECM for 10 consecutive attempts. 42 The EST signal was not received by ECM for 0.5 seconds when EST mode was enabled or when bypass mode was enabled. 43 Knock sensor signal was not received by ECM for 4 seconds when engine was running. 44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Left oxygen sensor voltage was over 0.75 volts for 30 seconds when the throttle angle was above 4% during closed loop operation. 52 Engine oil temperature was below -36? F after engine had been running for 30 minutes. 53 ECM detected a battery voltage either above 17.1 volts or below 8 volts. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received. 55 ECM detected a lean oxygen sensor voltage for 2 seconds during the power enrichment modes of operation. 56 Vacuum sensor voltage was either above 5 volts or below 0.46 volts. 61 Vacuum sensor voltage was between 0.76 and 4.89 volts when secondary port throttle valves were commanded closed, or the vacuum sensor voltage was below 1.7 volts when the secondary port throttle valves were commanded open. 62 Engine oil temperature sensor showed an oil temperature above 284? F after the engine had been running at least 30 minutes. 63 Right oxygen sensor was open showing a steady voltage between 0.35 and 0.55 volts for 60 seconds after the engine had been running for at least 2 minutes. 64 Right oxygen sensor voltage was below 0.2 volts for 50 seconds of closed loop operation. 65 Right oxygen sensor voltage was above 0.75 volts for 30 seconds of closed loop operation when the throttle angle was above 20% or below 2.7%. 66 A/C pressure sensor circuit was either open or shorted showing a voltage below 0.12 volts or above 4.86 volts for 10 seconds. GM
92 5.7L VIN 8

13 Oxygen Sensor voltage Stays between 0.35 and 0.55 volts for 60 Seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the, engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. On Brougham models the inlet air temperature sensor signal shows a temperature above 297? F with an engine speed greater than 35 MPH. 32 EGR open command did not change the MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 4 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation. On Brougham models the oxygen sensor voltage was under 0.2 volts. 45 Oxygen sensor voltage was over 0.750 volts for 30 seconds with a throttle angle above 20%. On Brougham models the oxygen sensor voltage was over 0.700 volts. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
92-93 3.3L VIN N MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds with a throttle angle above 4% after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 284? F after engine had been running for 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F with the engine running. 16 ECM sees a battery voltage above 16 volts for more than 10 seconds. 21 TPS voltage was above 1.95 volts for 5 seconds when the MAP sensor signal showed a high manifold vacuum or the TPS was above 4.9 volts at any time. 22 TPS voltage was under 0.24 volts for 4 seconds when ignition was on. 24 Vehicle speed sensor signal showed less than 3 MPH for 40 seconds with engine running and transmission in high gear. 26 Quad-driver sense voltage shows a low voltage when battery voltage should be present or if the sense voltage shows battery voltage when a low voltage should be present. 27 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 3rd gear, or drive gear was open when engine was first started. 28 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 3rd gear, or 4th gear switch was closed or grounded when vehicle was in 4th gear, or drive gear was open when the engine was first started. 29 4th gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or drive gear was open when the engine was first started. 31 Park/Neutral switch was open for 4 consecutive starts, or Park/Neutral switch was grounded with transmission in high gear and vehicle speed was above 45 MPH for 12 seconds. 34 MAF sensor did not give any signal for 4 seconds when engine was running. 38 Brake switch signal was not present when vehicle speed changed from above 35 MPH to 0 MPH 23 or more times. 39 TCC was commanded by the ECM when transaxle was in high gear for 15 seconds but engine speed did not indicate that the TCC was engaged. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor voltage was either above 3.5 volts or below 1.5 volts for 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 2 minutes of closed loop operation after engine had been running for at least 1 minute. 46 Power steering switch was closed while vehicle speed was over 40 MPH for more than 25 seconds. 48 Vehicle misfired. TPS was between 0.58 and 0.93 volts, engine RPM was between 1500 and 2500 and vehicle speed was between 50 and 60 MPH for 30 seconds. 51 MEM-CAL error. 66 A/C pressure sensor voltage was either above 4.9 volts or below 0.1 volt for 25 seconds. GM
92-93 3.8L & 3.8L Supercharged

13 Oxygen Sensor Circuit 14 Coolant Temperature Sensor Circuit 15 Coolant Sensor Circuit 16 System Voltage High/Low 17 Spark Reference Circuit 18 Cam/Crank Error 21 Throttle Position Sensor (TPS) Signal Voltage High 22 Throttle Position Sensor Circuit (Signal Voltage Low) 23 Intake Air Temp (IAT) Sensor (Low Temp Indicated) 24 Vehicle Speed Sensor (VSS) Circuit 25 Intake Air Temp (IAT) Sensor (High Temp Indicated) 26 Quad Driver (QDM) "A" Fault 31 PRNDL Switch Circuit 34 Mass Air Flow Sensor (MAF) Circuit 36 Transaxle Shift Control Problem 38 TCC Brake Input Circuit 39 Torque Converter Clutch (TCC) Circuit 41 Cam Sensor Circuit 42 Electronic Spark Timing (EST) Circuit 43 Electronic Spark Control (ESC) Circuit 44 Oxygen Sensor (O2S) Circuit (Lean Indication) 45 Oxygen Sensor (O2S) Circuit (Rich Indication) 51 Mem-Cal Error (Faulty or Incorrect Mem-Cal) 53 Exhaust Gas Recirculation (EGR) Fault 54 Exhaust Gas Recirculation (EGR) Fault 55 Exhaust Gas Recirculation (EGR) Fault 56 Quad-Driver "B" (QDM) Fault 57 Boost Control Problem 58 Security System (Fuel Enable Circuit) 61 Cruise Vent Solenoid Circuit 62 Cruise Vacuum Solenoid Circuit 63 Cruise System Problem (SPS Indicated Low) 65 Cruise Servo Position Sensor 66 Low A/C Refrigerant Charge 67 Cruise Switches Circuit 68 Cruise System Problem 69 A/C Head Pressure Switch Circuit 99 Power Management GM
92-93 4.3L VIN Z TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts for 2 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM, or the throttle angle was above 21% when engine speed was over 1200 RPM. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 70 seconds after engine had been running for 1 minute with a throttle angle between 2 and 20 percent. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. GM
92-93 4.9L VIN B

12 PCM did not receive distributor reference pulses for 4 seconds. 13 Oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature at a speed over 800 RPM. 14 Coolant temperature sensor signal indicates a temperature of over 313? F. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F. 16 Ignition voltage was either less than 10 volts or greater than 16 volts for 5 seconds. 17 Oxygen sensor voltage stays between 0.307 and 0.609 volts for 64 seconds. Engine was at normal operating temperature and over 800 RPM. 19 Fuel pump feedback voltage stayed above 7 volts for 4 seconds after ignition was turned on. 20 Fuel pump feedback voltage was 2 volts or less for 1 second. 21 TPS value was 72 degrees or more for 0.7 seconds. 22 TPS value was 1.3 degrees or less for 0.7 seconds when the engine was running at 600 RPM or more. 23 EST signal did not change when the ECM applied bypass voltage to the ignition module. 24 Vehicle speed was 0 for 3 seconds with transmission in drive or reverse and brake off when throttle angle was at least 17 degrees and engine RPM was 1400 or greater. 26 Throttle switch input to the PCM was closed for 1.8 seconds while the TPS was between 20 and 75 degrees. 27 Throttle switch was open when vehicle was coasting down with brake applied. Throttle angle was 16.5 degrees or less but RPM was greater than desired. 30 TPS was 14 degrees or more while ISC was retracting for 15 seconds, or TPS was 2 degrees while ISC was extending for 15 seconds. 31 MAP sensor was shorted to 5 volts for 0.2 seconds. 32 MAP sensor was open showing a reading of 0.5 volts or less for 0.2 seconds. 34 MAP sensor signal voltage was too high (low vacuum) for 15 seconds when throttle switch was closed. 37 MAT sensor was shorted showing a temperature of 313? F or more. 38 MAT sensor was open showing a temperature of -27? F or less. 39 Engine RPM was outside of the range expected for indicated vehicle speed indicating a VCC engagement problem. 40 Power steering switch was open when vehicle was at a speed of 45 MPH or greater. 41 CAM reference pulses were not received when distributor reference pulses were received at an engine speed of 1600 RPM or less. 42 Left oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater. (Eldorado & Seville only) 43 Left oxygen sensor was rich for more than 50 seconds when engine was warm and at 800 RPM or greater. (Eldorado & Seville only) 44 Right oxygen sensor was lean for more than 50 seconds when engine was warm and at 800 RPM or greater. 45 Right oxygen sensor was rich for more than 50 seconds when engine was warm and at 800 RPM or greater. 46 Left and right fuel control block learn values differ by more than 15 counts for 10 minutes. (Eldorado & Seville only) 47 PCM has received bad data from IPC for 3 seconds while engine speed was 500 RPM or more for 3 seconds. 48 EGR open command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. Vehicle speed was over 35 MPH and engine was warm. 51 MEM-CAL error. 52 PCM has lost primary battery power. 53 Distributor reference pulses were not received for 0.4 seconds when engine speed was greater than 568 RPM. 55 TPS zero point was out of range. 58 Pass Key fuel enable was not correct. 60 Transmission was not in drive when cruise control was engaged. 61 Cruise vent solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. 62 Cruise vacuum solenoid commanded OFF but solenoid remained ON, or commanded ON but solenoid remained OFF. 63 Cruise control servo position was at least 39% with cruise engaged. Vehicle speed was 20 MPH higher than the set speed for 0.5 seconds. 64 Vehicle speed increased more than 16 MPH in 1 second while cruise control was engaged. 65 Cruise control servo position was 6.3% or less for 1 second. 66 Engine RPM was 4800 or more for 0.25 seconds with cruise control engaged. 67 Cruise control Set/Coast or Resume/Accel switch was closed for 10 minutes. 68 With cruise control engaged the throttle angle was greater than 20 degrees and servo position sensor indicated a stroke greater than commanded. 70 Throttle position changed too rapidly without a corresponding change in MAP sensor signal when engine was running. 71 MAP sensor signal changed too rapidly while TPS signal was steady and engine speed did not change. 73 Coolant temperature sensor voltage has changed 0.3 volts in 1 second. 74 MAT sensor signal changed 7 degrees or more in 0.25 seconds. 75 Vehicle speed changed by 8 MPH or more in 1 second while MAP sensor remained steady with engine running and brakes not applied. 80 Block learn was 104 or less for 25 seconds with a throttle angle between 6 and 30 degrees and engine was warm. 85 The coast down throttle angle offset is more than 5 degrees from the zero value. 90 Vehicle speed cycles from 30 MPH to 0 at least 10 consecutive times with no VCC brake switch input. 91 Gear selector switch has either an open or a short causing an invalid signal for a forward or reverse gear. 92 Heated window signal was present at PCM for 10 minutes or more. 96 Throttle angle was 65 degrees or more for 12 seconds with transmission in drive or reverse and vehicle speed was 5 MPH or less with brake being applied. 97 Gear selector was moved from park or neutral to drive or reverse with engine speed over 2000 RPM but under 6 MPH. 98 At a vehicle speed under 6 MPH, the gear selector was moved from park or neutral into drive or reverse when engine speed was 600 RPM greater than determined by PCM. 99 Servo position sensor indicated that servo was still engaged after cruise control had been disengaged for 2 seconds. Throttle angle was above 20 degrees. GM
92-93 5.7L VIN P

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F. 15 Coolant temperature sensor signal indicates a temperature colder than -56? F. 16 A low resolution pulse was not detected by ECM within 720 high resolution timing pulses. 21 TPS voltage was above 2.5 volts for 3 seconds when the engine was running, or when the TPS was above 4.8 volts at any time. 22 TPS voltage was under 0.23 volts when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -31? F for 60 seconds after the engine has been running for 4 minutes. 24 Vehicle speed was 0 MPH when engine speed was between 900 and 3000 RPM and throttle position angle was less than 2% for 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F for 12 seconds after the engine has been running for 4 minutes. 26 ECM detected the wrong potential voltage at the #1 quad-driver module circuit for 20 seconds. 27 ECM detected the wrong potential voltage at the #2 quad-driver module circuit for 3 seconds. 28 ECM detected the wrong potential voltage at the #3 quad-driver module circuit for 3 seconds. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of the exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 1 second when throttle opening was under 3% and engine speed was above 500 RPM. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 700 RPM, or when TPS was greater than 20% with an engine speed above 700 RPM. 36 ECM detected less than 60 high resolution timing pulses between each low resolution pulse for 5 consecutive cycles. 41 EST circuit voltage was above 4.6 volts when engine speed was under 1500 RPM. 42 The EST circuit voltage was below 0.5 volts when engine speed was below 3000 RPM. 43 One or both of the knock sensors were either open or grounded for 5 seconds. 44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Left oxygen sensor voltage was over 0.7 volts for 50 seconds when the throttle angle was above 4% during closed loop operation. 51 PROM error. 52 Engine oil temperature was below -31? F after engine had been running for 30 minutes. 53 ECM detected a battery voltage either above 17.1 volts or below 8 volts. 55 ECM detected a lean oxygen sensor voltage for 3 seconds during the power enrichment modes of operation. 62 Engine oil temperature sensor indicated an oil temperature above 284? F after engine had been running for 30 minutes. 63 Right oxygen sensor was open showing a steady voltage between 0.35 and 0.55 volts for 60 seconds after the engine had been running for at least 2 minutes. 64 Right oxygen sensor voltage was below 0.2 volts for 50 seconds of closed loop operation. 65 Right oxygen sensor voltage was above 0.7 volts for 50 seconds of closed loop operation when the throttle angle was above 4%. 66 A/C pressure sensor circuit was either open or shorted showing a voltage below 0.12 volts or above 4.86 volts for 10 seconds. 67 ECM did not detect an A/C system pressure change of more than 9 psi when A/C clutch was engaged. 68 ECM detects voltage on the A/C status line for more than 20 seconds after ECM has disengaged the A/C relay. 69 ECM did not detect any voltage on A/C status line for 20 seconds after ECM had commanded A/C ON. 72 2nd or 3rd gear switch was open for 1.5 seconds when vehicle speed was above 30 MPH with engine speed greater than 5000 RPM and a throttle angle above 70%. GM
92-95 3.8L VIN L

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds when the TPS signal was above 0.55 volts. The engine had been running for at least 40 seconds with an engine temperature above 110? F. 14 Coolant temperature sensor signal indicates a temperature of over 284? F for 4 seconds after the engine had been running for at least 10 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -36? F for at least 4 seconds after the engine had been running for 2 seconds. 16 Charging system voltage was either below 9 volts or above 17 volts for 10 seconds. 17 PCM did not detect any spark reference pulses within 240 fuel control reference pulses (80 crank revolutions) while engine was running below 1200 RPM. 21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time. 22 TPS voltage was under 0.2 volts for 4 seconds when the ignition was on. 23 Inlet air temperature sensor signal showed an air temperature of -29? F for 4 seconds. 24 Vehicle speed sensor signal showed less than 3 MPH for 2 seconds when engine speed was greater than 3000 RPM and transmission has not been in park or neutral for more than 4 seconds. Or vehicle speed goes from above 18 MPH to 0 in less than 2 seconds without applying brake. 25 Inlet air temperature sensor signal showed an air temperature of over 218? F for 5 seconds when vehicle speed was greater than 35 MPH. 26 Quad-Driver sense voltage shows a low voltage when battery voltage should be present, or if the sense voltage shows battery voltage when a low voltage should be present for at least 5 seconds when the engine was running. 27 2nd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 2nd or 4th gear switch was open when engine was first started. 28 3rd gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 3rd or 4th gear switch was open when engine was first started. 29 4th gear switch was closed or grounded for 10 seconds when vehicle was in 4th gear, or 4th gear switch was open when engine was first started. 31 PRNDL indicates a gear other than park or neutral for 13 seconds for 3 consecutive startups when ignition was on, engine was off and vehicle speed was 0. Or the PRNDL status indicators (A, B, C, P) showed an incorrect combination of Lo and Hi for more than 10 seconds. 34 There was no MAF signal for over 4 seconds while engine was running. 36 Transmission solenoid "B" has failed in the Off position which caused transmission to be in 3rd when 1st gear was desired, or solenoid "B" failed in the On position which caused transmission to be in 1st when 3rd gear was desired. 38 The Torque Converter Clutch portion of the brake switch was open and caused the TCC to be inoperative. 39 The Torque Converter Clutch portion of the brake switch was inoperative for 30 seconds causing vehicle speed ratio to be outside of its window of operation. 41 Cam sensor signal was not received by PCM for the last 5 seconds while engine was running. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds. 44 Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts. 47 Momentary loss of power to Body Computer Module (BCM). Check that PROM is fully seated. (1993 Riviera only) 51 MEM-CAL error. 54 EGR #2 solenoid was out of range for 6 of 8 tests. 55 EGR #3 solenoid was out of range for 3 of 5 tests. 56 Quad-driver voltage was incorrect for 5 seconds on the circuit connected to QDM "B". 57 Boost control solenoid did not open bypass valve causing engine torque to be too high. 63 EGR flow was incorrect. EGR solenoid did not work properly. 64 EGR flow was incorrect. EGR solenoid did not work properly. GM
93 2.0L VIN H MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 40 seconds after engine has been running for 40 seconds with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 291? F or under -22? F after the engine has been running for 2 minutes. 19 The 58X signal (58 pulses per crank revolution) did not match with engine RPM. 21 TPS voltage was above 2.5 volts or below 0.2 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 23 Inlet Air Temperature Sensor signal showed an air temperature of less than 30? F or more than 302? F for 2 seconds after the engine has been running for 2 minutes. 24 Vehicle speed sensor signal showed less than 5 MPH. Vehicle was not in park or neutral and had an engine speed between 1600 and 4400 RPM and the MAP signal showed high manifold vacuum. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 15%. 44 Oxygen sensor voltage was under 0.35 volts for 25 seconds after the engine had been running for at least 2 minutes with a throttle angle above 5%. 45 Oxygen sensor voltage was over 0.55 volts for 51 seconds of closed loop operation after the engine had been running for at least 2 minutes with a throttle angle above 5%. 51 ECM error. GM
93 2.2L VIN 4

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 40 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature below -30? F or above 275? F for 3 seconds after the engine has been running for 2 minutes. 21 TPS voltage was above 3.9 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more and engine speed was less than 1750 RPM or TPS voltage was below 1.9 volts for 64 seconds. 23 Inlet Air Temperature Sensor signal showed an air temperature below -30? F or above 302? F for more than 2 seconds after the engine has been running for 2 minutes. 24 When engine speed was between 1700 and 3600 RPM and throttle position angle was less than 1%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet Air Temperature Sensor signal showed an air temperature over 304? F after the engine has been running for 5 minutes and 20 seconds and the vehicle speed was greater than 15 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was higher than 3.7 volts for 5 seconds when throttle opening was under 5%, or MAP sensor signal was lower than 0.3 volts when throttle opening was over 15%. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 44 Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.700 volts for at least 51 seconds of closed loop operation. Throttle angle was above 5% and engine had been running for at least 2 minutes. 51 EPROM error. 53 Battery voltage was higher than 17.1 volts for 0.2 seconds, or below 10 volts for 4 minutes. 55 Oxygen sensor voltage was less than 0.3 volts for 5 seconds of closed loop operation. 66 A/C refrigerant pressure voltage was either less than 0.19 volts or greater than 4.9 volts for 15 seconds, or the pressure voltage was above 4.0 volts when A/C clutch was not requested. GM
93 2.3L VIN D MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 285? F after engine had been running for at least 2 minutes, or if coolant temperature sensor was shorted to ground. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 60 seconds. 16 ECM did not receive 2X pulses while receiving 1X pulses. 19 7X reference signal problem. ECM has detected either too many or too few pulses between sync signal within 4 minutes. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet ATS signal showed an air temperature of -40? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet ATS signal showed an air temperature over 304? F after engine had been running for 5 minutes and vehicle speed was greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 27 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 28 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle, or the knock signal was present for 4.54 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.3 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 51 EPROM error. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds or less than 10 volts for 4 minutes with ignition on. 65 Fuel injector driver current did not reach 4 amps. Injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. GM
93 2.3L VIN A MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 285? F after engine had been running for at least 2 minutes, or if CTS was shorted to ground. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 60 seconds. 16 ECM did not receive 2X pulses while receiving 1X pulses. 19 7X reference signal problem. ECM has detected either too many or too few pulses between sync signal within 4 minutes. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -40? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 304? F after engine had been running for 5 minutes and vehicle speed was greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 27 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should he present. 28 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening over 15%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle, or the knock signal was present for 4.5 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.3 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 51 EPROM error. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds or less than 10 volts for 4 minutes with ignition on. 65 Fuel injector driver current did not reach 4 amps, injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds. GM
93 2.3L VIN 3 MFI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 30 seconds after engine had been running for at least 40 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 285? F after engine had been running for at least 2 minutes, or if coolant temperature sensor was shorted to ground. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for 60 seconds. 16 ECM did not receive 2X pulses while receiving 1X pulses. 19 7X reference signal problem. ECM has detected either too many or too few pulses between sync signal within 4 minutes. 21 TPS voltage was above 4.0 volts for 5 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more, or the TPS voltage was greater than 4.7 volts with throttle closed. 22 TPS voltage was under 0.2 volts for 5 seconds when the engine was running. 23 Inlet Air Temperature Sensor signal showed an air temperature of -40? F after the engine has been running for 5 minutes and 20 seconds. 24 Vehicle was not in park or neutral for 20 seconds when throttle position signal was over 7% with engine speed between 1600 and 3600 RPM and the MAP signal showed low manifold vacuum. 25 Inlet Air Temperature Sensor signal showed an air temperature over 304? F after engine had been running for 5 minutes and vehicle speed was greater than 15 MPH. 26 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 27 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 28 Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 12%. 34 MAP sensor signal voltage was too low (high vacuum) for 0.2 seconds when engine speed was under 1200 RPM or when engine speed was over 1200 RPM with throttle opening was over 15.2%. 35 Idle speed was over 175 RPM outside the desired engine speed commanded by the ECM for at least 5 seconds. 41 ECM had received 8 2X reference pulses without receiving any 1X reference pulses. 42 The EST circuit had an open or a ground and the signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle, or the knock signal was present for 4.54 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.3 volts for 50 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.75 volts for 50 seconds of closed loop operation. 51 EPROM error. 53 ECM sees a battery voltage of more than 17.1 volts for 0.2 seconds or less than 10 volts for 4 minutes with ignition on. 65 Fuel injector driver current did not reach 4 amps, injectors commanded "ON" longer than the calibrated pulse width and battery voltage was more than 9 volts for 10 seconds GM
93 3.1L VIN T

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds when the TPS signal was above 4%. The engine had been running for at least 2 minutes. 14 Coolant temperature sensor signal indicates a temperature of over 270? F after the engine had been running for at least 20 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -38? F for at least 1 second. 21 TPS voltage was above 3.8 volts for 10 seconds when engine was running and air flow was less than 17 gm/sec. 22 TPS voltage was under 0.25 volts for 3 seconds when the ignition was on. 23 Inlet air temperature sensor signal showed an air temperature of -31? F for 10 seconds after engine had been running for 4 minutes. 24 Engine Speed was between 2200 and 4400 RPM and transmission was not in park or neutral and TPS was less than 2% for 3 seconds. 25 Inlet air temperature sensor signal showed an air temperature of over 293? F for 3 seconds when vehicle speed was greater than 35 MPH. 32 The ECM opens each EGR control valve during deceleration and monitors the change in manifold vacuum. This code is set when the change in manifold vacuum is outside the normal range. 33 MAP sensor voltage was too high for 4.8 seconds when throttle angle was less than 2%. 34 MAP sensor voltage was too low for 1 second when engine speed was under 600 RPM, or MAP sensor voltage was too low for 1 second when engine speed was over 600 RPM and throttle angle was above 20%. 35 Engine idle speed is either 300 RPM above or below the desired idle speed for 50 seconds. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal was either above 4.6 volts or below 0.64 volts for at least 10 seconds. 44 Oxygen sensor voltage was under 0.25 volts for at least 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds in closed loop operation with a throttle angle between 3% and 45%. 51 MEM-CAL error. 53 ECM sees a battery voltage of more than 16.9 volts for 10 seconds. 54 Fuel pump voltage was less than 4 volts for 4 seconds. 62 Vehicle was in 2nd gear but 2nd gear signal switch was open, or vehicle was in 3rd gear but 3rd gear switch was open. 66 A/C pressure sensor voltage was either above 4.9 volts or below 0.1 volts for at least 5 seconds GM
93 5.7L VIN 7 TBI

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. 14 Coolant temperature sensor signal indicates a temperature of over 275? F for 2 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -27? F for 30 seconds after the engine has been running for at least 30 seconds. 21 TPS sensor voltage was above 2.5 volts for 8 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more. 22 TPS voltage was under 0.2 volts when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes. On Fleetwood the inlet air temperature signal shows a temperature below -20? F for 5 seconds at a speed less than 44 MPH. 24 When engine speed was between 1200 and 4400 RPM and throttle position angle was less than 3%, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds. 25 Inlet air temperature sensor signal showed an air temperature over 302? F after the engine has been running for 5 minutes. On Fleetwood the inlet air temperature signal shows a temperature above 297? F for 5 seconds at a speed less than 44 MPH. 26 Quad-Driver sense voltage shows a low voltage for 5 seconds where battery voltage should be present, or the sense voltage shows battery voltage for 25 seconds when a low voltage should be present. (Fleetwood only) 32 EGR open command did not change MAP sensor signal. Normal EGR flow should cause slight decrease in manifold vacuum which would change MAP sensor signal. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 4%. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was over 1200 RPM. On Fleetwood the engine speed was over 1000 RPM with a throttle position angle above 21%. 41 The EST signal was present when the circuit should have been grounded by the ignition module when it received bypass voltage under 1 volt. (Fleetwood only) 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194? F or the knock signal was present for 4 seconds or more during normal engine operation. 44 Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation. On Fleetwood the engine speed was over 1000 RPM with a throttle position angle above 21%. 45 Oxygen sensor voltage was over 0.75 volts for 30 seconds with a throttle angle greater than 20%. On Fleetwood the oxygen sensor voltage was 0.75 volts for 30 seconds in a closed loop with a throttle angle either greater than 20% or less than 2%. 46 Anti-Theft Pass Key signal was wrong when ignition was turned to start position. 51 PROM error. 54 Fuel pump voltage was not present at fuel pump sense line for 2 seconds after the ECM has sent the fuel pump on command. 55 ECM error. Replace ECM. (Except Fleetwood). GM
93 5.7L VIN J

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 2 minutes after start with a throttle angle above 5%. 14 Coolant temperature sensor signal indicates a temperature of over 266? F. 15 Coolant temperature sensor signal indicates a temperature colder than -26? F. 16 DIS fault line voltage was low for 2 seconds when EST was disabled. 21 TPS voltage was above 2.5 volts for 2 seconds when the engine was running, or when the TPS was above 4.8 volts at any time. 22 TPS voltage was under 0.23 volts when the engine was running. 23 Intake air temperature sensor signal showed an air temperature below -31? F for 1 seconds after the engine has been running for 4 minutes. 24 Vehicle speed was less than 3 MPH when engine speed was between 900 and 4400 RPM and throttle position angle was less than 2% for 4 seconds. 25 Intake air temperature sensor signal showed an air temperature over 302? F for 3 seconds after the engine has been running for 1 minutes. 31 Cam pulse was missing on the first pass through the internal ECM self test of the cam sensor, or for any 3-minute period. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of the exhaust gas. EGR position signal is also monitored to verify EGR movement. 33 MAP sensor signal voltage was too high (low vacuum) for 0.4 seconds when throttle opening was under 20% with an engine speed higher than 1250 RPM. 34 MAP sensor signal voltage was too low (high vacuum) when engine speed was under 700 RPM, or when TPS was greater than 20% with an engine speed above 700 RPM. 35 MAP sensor signal showed a low vacuum for 1 second when engine speed was more than 1500 RPM and throttle angle was less than 15%. 36 The DIS module did not sense the correct EST signal from ECM for 10 consecutive attempts. 42 The EST signal was not received by ECM for 0.5 seconds when EST mode was enabled or when bypass mode was enabled. 43 Knock sensor voltage was either above 3.62 volts or below 1.44 volts for 24 seconds or ECM did not receive the knock sensor signal. 44 Left oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation. 45 Left oxygen sensor voltage was over 0.75 volts for 30 seconds when the throttle angle was between 2.7% and 20% in closed loop operation. 52 Engine oil temperature was below -36? F after engine had been running for 30 minutes. 53 ECM detected a battery voltage either above 17.1 volts or below 8 volts. 54 Fuel pump voltage was less than 2 volts for 1.5 seconds since the last reference pulse was received. 55 ECM detected a lean oxygen sensor voltage for 2 seconds during the power enrichment modes of operation. 56 Vacuum sensor voltage was either above 4.8 volts or below 0.46 volts. 61 Vacuum sensor voltage was between 0.76 and 4.89 volts when secondary port throttle valves were commanded closed, or the vacuum sensor voltage was below 1.7 volts when the secondary port throttle valves were commanded open. 62 Engine oil temperature sensor showed an oil temperature above 284? F after the engine had been running at least 30 minutes. 63 Right oxygen sensor was open showing a steady voltage between 0.35 and 0.55 volts for 60 seconds after the engine had been running for at least 2 minutes. 64 Right oxygen sensor voltage was below 0.2 volts for 50 seconds of closed loop operation. 65 Right oxygen sensor voltage was above 0.75 volts for 30 seconds of closed loop operation when the throttle angle was above 20% or below 2.7%. 66 A/C pressure sensor circuit was either open or shorted showing a voltage below 0.5 volts or above 3.4 volts for 10 seconds. GM
93-94 1.9L VIN 9 TBI

11 Transaxle trouble code is present. 12 PCM self-diagnostic test is OK. 13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 20 seconds when the engine was at normal operating temperature. 14 Coolant temperature sensor signal indicates a temperature of over 284? F. 15 Coolant temperature sensor signal indicates a temperature colder than -31? F. 16 PCM desired current did not match with feedback current. 17 Coolant temperature signal did not change when PCM pull-up resistor switched. 19 Crankshaft position signal (6X) did not occur between each reference pulse for 3 consecutive times. 21 TPS voltage was above 4.9 volts. 22 TPS voltage was under 0.2 volts. 23 Inlet air temperature sensor signal showed an air temperature of -22? F. 25 Inlet air temperature sensor signal showed an air temperature over 257? F. 26 Any of the quad-driver module circuits had an open or short for 25 seconds. 27 Any of the quad-driver module circuits had an open or short for 5 seconds. 32 EGR system fault. Fuel mixture did not change when EGR solenoid was commanded ON and OFF. 33 MAP sensor signal voltage was greater than 4.2 volts when throttle angle was less than 5%. 34 MAP sensor signal voltage was less than 2 volts when engine speed was less than 1200 RPM. 35 Idle speed was either above or below desired idle. 41 Electronic ignition circuit was either open or grounded. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ESC circuit voltage was out of range for 10 seconds. 44 Oxygen sensor voltage was under 0.3 volts for 3 minutes of closed loop operation. 48 PCM detected extra or missing crank reference pulses. 49 IAC was working improperly. Engine idle RPM was too high. 51 PROM error. 52 PCM sees a battery voltage either above 17 volts or below 11 volts. 53 Knock sensor could not eliminate engine noise by retarding timing. 54 Either the MAP sensor, Handwheel sensor, TPS, or all three sensors were grounded to 0 volts. 55 Analog to digital signal conversion was incorrect. 58 Battery voltage has changed more than 3 volts instantly. 63 Option check-sum error. Invalid combinations of tire sizes or other options. 71 Engine coolant temperature was above 244? F. 72 Engine coolant temperature was below 32? F after engine had been running for 5 minutes. 73 Engine coolant temperature changed more than 59? F in 0.1 second. 74 Engine coolant temperature sensor reading was less than the transaxle temperature sensor reading. 75 Inlet air temperature reading changed more than 59? F in 0.1 second. 76 MAP sensor signal did not change with a corresponding change in the TPS. 81 PCM did not receive the signal or received the incorrect signal from the ABS controller. 82 PCM is out of calibration. Recalibrate PCM. If code 82 still exists then replace PCM. 83 Engine coolant switch was open for 20 seconds when engine was running. 84 Communications error between engine control module and transaxle controller GM
93-95 1.9L VIN 7

11 Transaxle trouble code is present. 12 PCM self-diagnostic test is OK. 13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 20 seconds when the engine was at normal operating temperature. 14 Coolant temperature sensor signal indicates a temperature of over 284? F. 15 Coolant temperature sensor signal indicates a temperature colder than -31? F. 16 PCM desired current did not match with feedback current. 17 Coolant temperature signal did not change when PCM pull-up resistor switched. 19 Crankshaft position signal (6X) did not occur between each reference pulse for 3 consecutive times. 21 TPS voltage was above 4.9 volts. 22 TPS voltage was under 0.2 volts. 23 Inlet air temperature sensor signal showed an air temperature of -22? F. 25 Inlet air temperature sensor signal showed an air temperature over 257? F. 26 Any of the quad-driver module circuits had an open or short for 25 seconds. 27 Any of the quad-driver module circuits had an open or short for 5 seconds. 32 EGR system fault. Fuel mixture did not change when EGR solenoid was commanded ON and OFF. 33 MAP sensor signal voltage was greater than 4.2 volts when throttle angle was less than 5%. 34 MAP sensor signal voltage was less than 2 volts when engine speed was less than 1200 RPM. 35 Idle speed was either above or below desired idle. 41 Electronic ignition circuit was either open or grounded. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 The ESC circuit voltage was out of range for 10 seconds. 44 Oxygen sensor voltage was under 0.3 volts for 3 minutes of closed loop operation. 48 PCM detected extra or missing crank reference pulses. 49 IAC was working improperly. Engine idle RPM was too high. 51 PROM error. 52 PCM sees a battery voltage either above 17 volts or below 11 volts. 53 Knock sensor could not eliminate engine noise by retarding timing. 54 Either the MAP sensor, Handwheel sensor, TPS, or all three sensors were grounded to 0 volts. 55 Analog to digital signal conversion was incorrect. 58 Battery voltage has changed more than 3 volts instantly. 63 Option check-sum error. Invalid combinations of tire sizes or other options. 71 Engine coolant temperature was above 244? F. 72 Engine coolant temperature was below 32? F after engine had been running for 5 minutes. 73 Engine coolant temperature changed more than 59? F in 0.1 second. 74 Engine coolant temperature sensor reading was less than the transaxle temperature sensor reading. 75 Inlet air temperature reading changed more than 59? F in 0.1 second. 76 MAP sensor signal did not change with a corresponding change in the TPS. 81 PCM did not receive the signal or received the incorrect signal from the ABS controller. 82 PCM is out of calibration. Recalibrate PCM. If code 82 still exists then replace PCM. 83 Engine coolant switch was open for 20 seconds when engine was running. 84 Communications error between engine control module and transaxle controller. GM
93-95 3.4L VIN X

13 Oxygen sensor voltage stays between 0.35 and 0.55 volts for 25 seconds. The engine had been running for at least 2 minutes and the TPS was above 4%. 14 Coolant temperature sensor signal indicates a temperature of over 270? F after the engine had been running for 20 seconds. 15 Coolant temperature sensor signal indicates a temperature colder than -37? F when the engine was running. 21 TPS voltage was above 3.78 volts for 1.25 seconds. 22 TPS voltage was under 0.25 volts for 10 seconds when the engine was running. 23 Inlet air temperature sensor signal showed an air temperature of -31? F for 10 seconds after the engine has been running for 4 minutes. 24 Vehicle speed sensor signal showed less than 2 MPH for 3 seconds when throttle position signal was less than 2% with engine speed between 2200 and 4400 RPM with the vehicle in gear. 25 Inlet air temperature sensor signal showed an air temperature of over 293? F and vehicle speed was greater than 1 MPH. 32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas. 33 MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 6%. 34 MAP sensor signal voltage was too low (high vacuum) for 22 seconds when engine speed was under 625 RPM, or when engine speed was over 625 RPM and throttle opening was over 20% for 22 seconds. 35 Idle speed was over 200 RPM outside the desired engine speed commanded by the ECM for 50 seconds. 39 Transaxle clutch switch has failed 4 consecutive times. Vehicle was at normal operating temperature and the speed went from 0 to 40 MPH or more and back to 0 again. 41 MEM-CAL error. 42 The EST signal did not change when the ECM applied bypass voltage to the ignition module. 43 Knock sensor signal voltage was either above 4.8 volts or below 0.64 volts for 10 seconds. 44 Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation. 45 Oxygen sensor voltage was over 0.7 volts for 50 seconds of closed loop operation. Engine had been running for at least 1 minute with the throttle angle between 3% and 45%.

[TAKAISIN ETUSIVULLE]