Pontiac OBD/OBD2 Codes >> Firebird – Grand Prix – Montana/SV6 – Sunfire – Trans Sport (1995 – 2008)

ModelYearEngine identificationSystem
Firebird 3.8L1995-02VIN  position 8 = KGM
Firebird 5.7L1996-02VIN  position 8 =  G/PGM
Grand Prix 3.1 L1996-03VIN  position 8  = M/JGM
Grand Prix 3.4L1996VIN  position 8 = XGM
Grand Prix 3.8/5.3L1997-08VIN  position 8 = 1/2/4/C/KGM
Montana/SV6 3.4/3.5L1999-07VIN  position 8 = E/LGM
Sunfire 2.2L1995-05VIN  position 8  =  4/5/FGM
Sunfire 2.3L1995VIN  position 8 =  DGM
Sunfire 2.4L1996-02VIN  position 8 =  TGM
Trans Sport 3.4L1996-98VIN  position 8 = EGM

General information

  • Malfunction indicator lamp (MIL) will illuminate or flash if certain faults are recorded.
  • ECM operates in backup mode if sensors fail, to enable vehicle to be driven to repair shop.


• Trouble codes can only be displayed by using a Scan Tool connected to the data link connector (DLC) 1 or 2.


• After the faults have been rectified, the manufacturer recommends that trouble codes are erased by using a Scan Tool connected to the data link connector (DLC).

Trouble code  identification

Scan codeFault locationProbable cause
PO, P2,UORefer to OBD-II trouble code tables
P1101Intake air flow -incorrectWiring, mechanical fault, engine coolanttemperature (ECT) sensor, barometric pressure (BARO) sensor, intake air temperature (IAT) sensor, manifold absolute pressure (MAP) sensor, mass air flow (MAF) sensor, throttle position (TP) switch
P1106Manifold absolute pressure (MAP) sensorvoltage high, intermittentWiring open circuit/short circuit to positive, poor connections
P1107Manifold absolute pressure (MAP) sensorvoltage low, intermittentWiring short circuit to ground, poor connections
P1111Intake air temperature (IAT) sensor -voltage high,intermittentWiring open circuit/short to positive, poor connections
P1112Intake air temperature (IAT) sensor -voltage low,intermittentWiring short circuit to ground
P1114Engine coolant temperature (ECT) sensorvoltage low, intermittentWiring short circuit to ground, poor connections
P1115Engine coolant temperature (ECT) sensorvoltage high, intermittentWiring open circuit/short to positive, poor connections
P1120Throttle motor position sensor 1 -circuitmalfunctionWiring, throttle control module
P1121Throttle position (TP) sensor -voltage high,intermittentWiring open circuit/short to positive, poor connections
P1122Throttle position (TP) sensor -voltage low, intermittentWiring open circuit/short to ground, poor connections
P1125Accelerator pedal position (APP) sensor 1/2/3signal malfunctionWiring, APP sensor, ECM
P1133Oxygen sensor (02S)/heated oxygen sensor(H02S) 1, bank 1 -insufficient switchingWiring, exhaust system leaking, 02S/H02S
P1134Heated oxygen sensor (H02S) 1, bank 1 slow responseWiring, oxygen sensor heater, exhaust system leaking, H02S
P1137Heated oxygen sensor (H02S) 2, bank 1 voltage lowWiring, exhaust system leaking, H025
P1138Heated oxygen sensor (H02S) 2, bank 1 voltagehighWiring, H025
P1153Heated oxygen sensor (H02S) 1, bank 2insufficient switchingWiring, oxygen sensor heater, exhaust systemleaking, H025
P1154Heated oxygen sensor (H02S) 1, bank 2slow responseWiring, oxygen sensor heater, exhaust system leaking, H02S
P1171Fuel system -lean during accelerationFuel filter, fuel pump, H025, injectors
P1189Engine oil pressure warning lamp switch -circuit malfunctionWiring, engine oil pressure warning lamp switch
P1200Injectors -circuit malfunctionWiring open circuit/short circuit to ground/short circuit to positive, injectors, ECM
P1220Throttle motor position sensor 2 -circuit malfunctionWiring, throttle control module
P1221Throttle motor position sensor 1/2 signal variationWiring, throttle control module
P1222Injector control , circuit monitor -malfunctionInjector, wiring
P1258Engine overheatingCooling system, engine coolant temperature (ECT) sensor
P1260Fuel pump, control signal -circuit malfunctionWiring, fuel pump control module, ECM
P1271Accelerator pedal position (APP) sensor 1/2signal variationWiring, APP sensor, ECM
P1272Accelerator pedal position (APP) sensor 2/3signal variationWiring, APP sensor, ECM
P1273Accelerator pedal position (APP) sensor 1/3signal variationWiring, APP sensor, ECM
P1275Accelerator pedal position (APP) sensor 1 circuitmalfunctionWiring, APP sensor, ECM
P1276Accelerator pedal position (APP) sensor 1 rangeperformanceWiring, APP sensor, ECM
P1280Accelerator pedal position (APP) sensor 2 circuitmalfunctionWiring, APP sensor, ECM
P1281Accelerator pedal position (APP) sensor 2 range performanceWiring, APP sensor, ECM
P1285Accelerator pedal position (APP) sensor 3 circuitmalfunctionWiring, APP sensor, ECM
P1286Accelerator pedal position (APP) sensor 3 range performanceWiring, APP sensor, ECM
P1336Crankshaft position (CKP) sensor -variation not learnedLearning procedure not performed
P1350Ignition control system, bypass circuit -circuitmalfunctionWiring, poor connections, ICM, ECM
P1351Ignition control system, coil -voltage highWiring open circuit, ICM, ECM
P1352Ignition control system, bypass circuit voltagehighWiring open circuit, ICM, ECM
P1361Ignition control system, IC circuit -voltage lowWiring, circuit short circuit to ground, poor connections, ICM, ECM
P1362Ignition control, bypass circuit -voltage lowWiring short circuit to ground, ICM, ECM
P1371Ignition control’reference signal, low/high resolution -low signal lostWiring,ICM
P1374Crankshaft position (CKP) sensor, high to lowresolution frequency -signal variationWiring, wiring routed near spark plug wires, ignition coils arcing/tracking, ICM, ECM
P1380Antilock brake system (ABS)/traction controlsystem (TCS), rough road signal to ECM -malfunctionASS trouble coders) stored
P1381Antilock brake system (ABS)/traction controlsystem (TCS), rough road signal to ECM -nocommunicationWiring, poor connections, ASS
P1400Cold start emission control -malfunctionIntake/exhaust leak/blockage, mechanical fault,idle speed control (ISC) system, ignition control,engine coolant temperature (ECT) sensor, H02S
P1404Exhaust gas recirculation (EGR) valve -not fullyclosingWiring, poor connections, EGR valve position sensor, EGR solenoid
P1406Exhaust gas recirculation (EGR) valve positionsensor range performanceWiring, EGR valve tight/sticking, EGR valve position sensor
P1415Secondary air injection (AIR) system, bank 1Wiring, hoses blocked/leaking, AIR valve
P1416Secondary air injection (AIR) system, bank 2Wiring, hoses blocked/leaking, AIR valve
P1441Evaporative emission (EVAP) system -leak detectedHose connection(s), EVAP canister, EVAP canister purge valve
P1442Evaporative emission (EVAP) system vacuumswitch -circuit malfunctionHoses blocked/leaking, wiring, EVAP canister, ECM
P1483Engine cooling system -performanceCooling system, engine coolant temperature(ECT) sensor, intake air temperature (IAT) sensor
P1508Idle air control (lAC) valve -low rpmWiring open circuit/short circuit to ground/short circuit to positive, lAC valve, throttle valve tight/sticking
P1509Idle air control (lAC) valve -high rpmWiring open circuit/short circuit to ground/short circuit to positive, lAC valve, throttle valve tight/sticking
P1514Throttle control unit, intake air flow -excessiveThrottle control unit, MAP sensor, CMP sensorsignal, ECM
P1515Throttle command/actual throttle position -signalvariationWiring, throttle valve sticking, throttle control module
P1516Throttle command/actual throttle position -signal variationWiring, throttle valve sticking, throttle control module
P1517Throttle control module -malfunctionThrottle control module
P1518Throttle control module/ECM -communicationmalfunctionWiring, throttle control module, ECM
P1519Throttle motor position sensor 1 -signalmalfunctionThrottle control module
P1523Throttle control unit, closed throttle position -performanceThrottle valve movement restricted, throttle control unit
P1532AlC refrigerant temperature sensor -voltage lowWiring open circuit/short circuit to ground, AlC refrigerant temperature sensor, ECM
P1533AlC refrigerant temperature sensor -voltage highWiring open circuit/short circuit to ground, AlC refrigerant temperature sensor, ECM
P1539AlC compressor clutch relay -voltage highWiring, AlC compressor clutch relay, ECM
P1543AlC system -performanceRefrigerant low, wiring, AlC refrigerant pressure sensor, AlC evaporator temperature sensor, ECM
P1545AlC compressor clutch relay -voltage lowWiring, AlC compressor clutch relay, ECM
P1546AlC compressor clutch relay -circuit malfunctionWiring, AlC compressor clutch relay, ECM
P1554Cruise control status circuit -high voltageWiring open circuit/short circuit to ground, cruise control module, ECM
P1571Traction control system (TCS), torque request signal malfunctionWiring, poor connections, ABSITCS
P1572Traction control system (TCS), active signal malfunctionWiring short to ground, ABSITCS, ECM
P1573Engine control module (ECM), antilock brakesystem (ABS)/traction control system (TCS)communication -malfunctionWiring, poor connections, ABS control module, ECM
P1574Brake pedal position (BPP) switch, voltage highWiring, ABS
P1585Cruise control system, inhibit output circuitWiring, poor connections, cruise control motor/actuator, ECM
P1586Cruise control system, brake switch 2 -circuit malfunctionWiring, poor connections, BPP switch
P1600Engine control module (ECM) -malfunctionEngine control module (ECM)
P1601CAN data bus, engine control module(ECM)/antilock brake system (ABS)/traction control system (TCS)/instrumentation control module/diagnostic control module -not allmodules communicatingWiring, poor connections, ECM, ABSITCS, diagnostic control module, instrumentation control module
P1621Engine control module (ECM) memory performanceECM
P1626Engine control module (ECM) -fuel enable signal lostWiring, poor connections, immobilizer control module, ECM
P1627Engine control module (ECM) malfunctionEngine control module (ECM)
P1629Engine control module (ECM) -fuel enable signal not receivedIncorrect ignition key, wiring, poor connections, immobilizer control module, ECM
P1630Engine control module (ECM). immobilizer code leaming modeECM immobilizer code programming not completed
P1631Engine control module (ECM) -incorrect immobilizer codeIncorrect key, immobilizer code not programmed
P1632Engine control module (ECM) -fuel disable signalreceivedFuses, SCM, immobilizer code
P1635Engine control module (ECM). sensor supplyvoltage -circuit malfunctionWiring, poor connections, TP sensor, MAP sensor, EGR valve position sensor, fuel tank pressure (FTP) sensor, ECM
P1637Alternator warning lamp, control signal -circuitmalfunctionWiring, instrument panel, ECM
P1639Engine control module (ECM), sensor supplyvoltage -circuit malfunctionWiring, poor connections, AlC refrigerant pressure sensor, ECM
P1640Engine control module (ECM), quad driver/output driver -circuit malfunctionWiring, ECM controlled components, ECM III
P1641 0Malfunction indicator lamp (MIL) -circuit malfunctionWiring, poor connections, MIL, ECM
P1641 f)AlC compressor clutch relay -circuit malfunctionWiring open circuit/short circuit to ground, AlC compressor clutch relay, ECM
P1641 DEngine coolant blower motor relay 1 -circuitmalfunctionWiring, engine coolant blower motor relay, ECM
P1642 DEngine coolant blower motor relay 2 & 3 circuitmalfunctionWiring, engine coolant blower motor relay(s), ECM
P1642 9Engine oil change warning lamp -circuit malfunctionWiring, ECM
P1642 IIISecondary air injection (AIR) pump relay circuit malfunctionWiring, AIR pump relay, ECM
P1643 DEngine speed (RPM), engine control module (ECM)output signal -circuit malfunctionWiring, tachometer, ECM
P1643 9Fuel pump, control signal -circuit malfunctionWiring, fuel pump control module, ECM
P1644Traction control system (TCS), delivered torque signal -malfunctionWiring, poor connections, ECM
P1645Supercharger (SC) bypass valve, control signal -circuit malfunctionWiring, SC bypass valve, ECM
P1650Engine control module (ECM), quad driver/output driver -circuit malfunctionWiring, ECM controlled components, ECM III
P1651Engine coolant blower motor relay 1 -circuitmalfunctionWiring, engine coolant blower motor relay, ECM
P1652 DEngine control module (ECM), vehicle speedsensor (VSS) output signal -circuit malfunctionWiring, poor connections, ECM
P1652 9Engine coolant blower motor relay 2 & 3 circuit malfunctionWiring, engine coolant blower motor relay(s), ECM
P1653 ~Fuel gauge, control signal -circuit malfunctionWiring, ECM
P1653 0Engine oil level ‘low’ warning lamp, control signal -circuit malfunctionWiring short circuit to ground, ECM
P1653 EJTraction control system (TCS), delivered torque signal -malfunctionWiring, poor connections, ECM
P1654AlC compressor clutch relay -circuit malfunctionWiring open circuit/short circuit to ground, AlC compressor clutch relay, ECM
P1655Evaporative emission (EVAP) canister purge valve -circuit malfunctionWiring open circuit/short circuit to ground, EVAP canister vent valve, ECM
P1657Skip shift solenoid -circuit malfunctionWiring, skip shift solenoid, ECM
P1660Engine control module (ECM), quad driver/output driver -circuit malfunctionWiring, ECM controiled components, ECM liJ
P1661Malfunction indicator lamp (MIL) -circuit malfunctionWiring, MIL, ECM
P1662Cruise control, inhibit output circuit malfunctionWiring open circuit/short circuit to ground, cruise control motor/actuator, cruise control module, ECM
P1663Alternator warning lamp, control signal -circuit malfunctionWiring, instrument panel, ECM
P1664Skip shift warning lamp -circuit malfunctionWiring, skip shift warning lamp, ECM
P1665Evaporative emission (EVAP) canister vent valve -circuit malfunctionWiring open circuit/short circuit to ground, EVAP canister vent valve, ECM
P1667 DReverse inhibit solenoid -circuit malfunctionWiring, reverse inhibit solenoid, ECM
P1667 aFuel pump, control signal -circuit malfunctionWiring, fuel pump control module, ECM
P1668Alternator ‘L’ terminal -circuit malfunctionWiring, voltage regulator, alternator, ECM
P1670Engine control module (ECM), quad driver/output driver -circuit malfunctionWiring, ECM controlled components, ECM liJ
P1671Malfunction indicator lamp (MIL) -circuit malfunctionWiring open circuit/short circuit to ground/short circuit to positive, MIL, ECM
P1672Engine oil level ‘low’ warning lamp, control signal -circuit malfunctionWiring short circuit to ground, engine oil level,ECM
P1673Engine coolant ‘hot’ warning lamp, control signal -circuit malfunctionWiring, instrument panel, cooling system, ECM
P1676Evaporative emission (EVAP) canister purge valve -circuit malfunctionWiring open circuit/short circuit to ground, EVAP canister purge valve, ECM
P1680Engine control module (ECM) -malfunctionEngine control module (ECM)
P1681Engine control module (ECM) -malfunctionEngine control module (ECM)
P1682Engine control module (ECM) -ignition power supply less than 10 VWiring, ECM
P1683Engine control module (ECM) -malfunctionEngine control module (ECM)
P1689Traction control system (TCS), delivered torque signal -malfunctionWiring, poor connections, ECM
P1750Torque converter clutch (TCC)solenoid/transmission shift control valve/transmission pressure control solenoid -circuit malfunctionWiring, TCC solenoid/transmission shift control valve/transmission pressure control solenoid, TCM, ECM
P1810Transmission fluid pressure (TFP) switch -manual valve positionFluid level low, wiring, selector lever linkageincorrectly adjusted, ECM
P1811Shift time too long -adaptation limit reachedFluid level low, transmission mechanical fault
P1814Torque converter clutch (TCC) -over-stressedFluid level low, fluid condition, transmission mechanical fault
P1815Transmission fluid pressure (TFP) switch -invalidgear selectionWiring, selector lever linkage incorrectly adjusted, TFP switch, ECM
P1816Transmission fluid pressure (TFP) switch-invalidgear selectionWiring, selector lever linkage incorrectly adjusted, TFP switch, ECM
P1817Transmission fluid pressure (TFP) switch -invalidgear selectionWiring, selector lever linkage incorrectly adjusted, TFP switch, ECM
P1818Transmission fluid pressure (TFP) switch -invalidgear selectionWiring, selector lever linkage incorrectly adjusted, TFP switch, ECM
P1819Transmission range (TR) switch, signals ‘AIS/C &P’ -signal variationWiring, TR switch
P1820Transmission range (TR) switch, signal ‘A’ voltage lowWiring short to ground, TR switch
P1822Transmission range (TR) switch, signal’S’ voltage highWiring, TR switch
P1823Transmission range (TR) switch, signal ‘P’ voltage lowWiring short to ground, TR switch
P1825Transmission range (TR) switch, signals ‘AIS/C &P’ incorrect signalWiring, TR switch
P1826Transmission range (TR) switch, signal ‘C’voltage highWiring, TR switch
P1860Torque converter clutch (TCC) solenoid -circuitmalfunctionWiring open circuit/short circuit to ground, TCC solenoid, ECM
P1870Torque converter clutch (TCC) -slip speed excessiveTransmission fluid level, wiring, TCC solenoid, ECM
P1887Torque converter clutch (TCC) release switch -circuit malfunctionWiring open circuit, TCC solenoid release switch, ECM
P1915Transmission range (TR) switch, signals ‘AIS/C &P’ -incorrect signal, while crankingWiring, TR switch
P3401Cylinder cut-out solenoid, cylinder 1 malfunctionWiring, cylinder cut-out solenoid, mechanical fault, ECM
P3425Cylinder cut-out solenoid, cylinder 4 malfunctionWiring, cylinder cut-out solenoid, mechanical fault, ECM
P3441Cylinder cut-out solenoid, cylinder 6 malfunctionWiring, cylinder cut-out solenoid, mechanical fault, ECM
P3449Cylinder cut-out solenoid, cylinder 7 malfunctionWiring, cylinder cut-out solenoid, mechanical fault, ECM
U1000CAN data bus -communication malfunctionWiring, BCM, ECM, ABS/TCS, instrumentation control module, SOM
U1001CAN data bus -loss of serial communicationWiring, BCM, ECM, instrumentation controlmodule, SOM
U1016CAN data bus, engine control module(ECM)/antilock brake system (ABS)/traction control system (TCS)/instrumentation controlmodule/diagnostic control module -loss of serialcommunicationWiring, poor connections, ECM, ABS/TCS, diagnostic control module, instrumentation control module
U1254CAN data bus -loss of serial communicationWiring, BCM, ECM, instrumentation control module, SOM
U1255CAN data bus -communication malfunctionWiring, BCM, ECM, ABS/TCS, instrumentation control module, SOM
U1300CAN data bus -signal lowWiring
U1301CAN data bus -signal highWiring
U1304CAN data bus -communication malfunction withABSITCSWiring, ABS/TCS, ECM
U1305CAN data bus -signal high or lowWiring
U1500Vehicle communication interface module (VCIM)-malfunctionVCIM
U1650CAN data bus -communication malfunction withABSfTCSWiring, steering angle sensor, ABS/TCS
U1651CAN data bus -communication malfunction withABSITCSWiring, steering angle sensor, ABS/TCS