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Diagnostic Trouble Code numbers are read by plugging a code reader or scan tool into the vehicle diagnostic connector (usually located under the instrument panel near the steering column) that can read vehicle manufacturer enhanced or P1 c odes (not just generic or P0 codes). The presence of a code will turn on the Check Engine Light. The light will remain on until the code has been erased. The code number does not tell you which part has failed. It only indicates a possible fault has been detected in the circuit, system or sensor described. Further testing is usually required to isolate the fault BEFORE repairs are made.
For vehicle specific diagnostic charts and vehicle specific repair information, refer to a service manual, or get a subscription to the AC Delco Tech Info website.
The following is a partial listing of common General Motors specific "P1" enhanced OBD II fault codes:
NOTE: For some code numbers, there may be more than one definition because the same number may be used for different faults on different model years or models.
P1500....Starter signal circuit
P1501....Vehicle speed sensor circuit intermittent, or Theft deterrent system
P1502....Theft deterrent system no password received ( Click Here for help troubleshooting Anti-Theft System problems)
P1503....Theft deterrent system password improper
P1508....Idle Air Control system -- idle too low
P1509....Idle Air Control system -- idle too high
P1510....Backup power supply
P1511....Throttle Control System - backup system performance
P1514....Airflow to throttle position sensor too high
P1515....Electronic throttle module throttle position
P1516....Electronic throttle module throttle postion
P1517....Electronic throttle module, or TAC module fault
P1518....No communication between electronic throttle module and PCM
P1519....Throttle Actuator Control Module ( Click Here for help troubleshooting Electronic Throttle Control problems)
P1520....Park/Neutral Switch circuit, gear indicator system
P1523....Electronic throttle control throttle return
P1524....Throttle Position Sensor out of range or misadjusted
P1525....Throttle Body Service required
P1526....Throttle position learn process not complete
P1527....Transmission range/pressure switch comparison
P1528....Governor control system
P1530....Ignition timing adjustment switch circuit, or A/C Refrigerant Pressure Sensor error
P1531....A/C low refrigerant ( Click Here for help on how to Recharge your A/C)
P1532....Engine coolant temperature sensor intermittent, or A/C Evaporator Temperature circuit low voltage
P1533....A/C Low Side Temperature Sensor circuit
P1535....A/C High Side Temperature Sensor circuit
P1536....A/C system ECT over-temperature
P1537....A/C request circuit voltage low
P1538....A/C request circuit voltage high
P1539....A/C High Pressure Switch circuit voltage high
P1540....A/C system high pressure ( CLick Here for help troubleshooting Air Conditioning problems)
P1542....A/C system high pressure or high temperature
P1543...A/C system performance out of range
P1545....A/C Clutch Relay Control circuit
P1546....A/C Clutch Relay control circuit voltage low
P1550....Cruise control, motor actuator circuit
P1554....Speed Control status circuit
P1555....Electric Variable Orifice fault (Saturn)
P1558....Speed Control (SPS low)
P1560....Speed Control System/Transaxle not in Drive
P1561....Speed Control Vent Solenoid
P1562....Speed Control Vacuum Solenoid
P1564....ECM battery voltage loss (Catera only), or speed control system/vehicle acceleration too high
P1565....Speed Control Servo Position Sensor
P1566....Speed Control System/Engine RPM too high
P1567....Speed Control Master Switch
P1568....Speed Control (SPS high)
P1570....Speed Control System/Traction Control active
P1571....Traction Control System desired torque circuit ( Click Here for help troubleshooting Traction Control problems)
P1572....Traction Control System active circuit voltage low too long
P1573....PCM/EBTCM serial data circuit communication malfunction
P1574....EBTCM system/stop lamp circuit voltage high
P1575....Stop lamp control circuit (97-98 Corvette only), or extended travel brake switch circuit voltage high
P1576....Brake Booster Vacuum Sensor circuit voltage high ( Click Here for help troubleshooting Power Brake problems)
P1577....Brake Booster Vacuum Sensor circuit voltage low
P1578....Brake Booster Vacuum Sensor circuit low vacuum
P1579....Park/Neutral to Drive/Reverse at high throttle angle
P1580....Cruise Control Module move circuit, low voltage
P1581....Cruise Control Module move circuit, high voltage
P1582....Cruise Control Module direction circuit, low voltage
P1583....Cruise Control Module direction circuit, high voltage
P1584....Cruise control disabled
P1585....Cruise Control inhibit output circuit
P1586....Cruise Control Brake Switch 2 circuit
P1599....Engine stall detected
P1600....Powertrain control module battery, or loss of communication between PCM and TCM
P1601....ECM over-temperature
P1602....PCM to ABS module communication problem
P1603....Serial data communication problem
P1604....IPC Serial data communication problem
P1605....Serial data communication problem with HVAC module
P1607....Engine Oil Level Switch circuit
P1610....Loss of PZM serial data, or failure of body function controller (1997 Cutlass & Malibu only)
P1611....Loss of CVRTD serial data
P1617....Engine Oil Level Switch circuit
P1619....Engine Oil Life Monitor reset circuit, or oil life error
P1620....Engine coolant low (Saturn)
P1621....Powertrain control module memory error, or VCM EEPROM performance (1998 5.7L only)
P1623....PCM Prom error, or Transaxle Temperature Sensor fault (Saturn)
P1624....Powertrain control module software reset, or customer snapshot data available (Saturn)
P1625....Powertrain control module system reset, or TCM flash checksum fault (Saturn)
P1626....Anti-theft system fuel enable circuit (Passkey error)
P1627....A/D performance, or Powertrain Control Module fault
P1628....PCM Engine Control Temperature Pull-up Resistor, or Engine Coolant Temperature Sensor circuit resistor fault
P1629....Anti-theft divide cranking signal or Passkey cranking error ( Click Here for help troubleshooting Anti-Theft System problems)
P1630....System voltage too high/too low, or ECM immobilizer learning mode (Cavalier & Monte Carlo only)
P1631....Oxygen sensor #1 slow response, or anti-theft password incorrect
P1632....Anti-theft fuel disable signal received
P1633....Ignition power circuit low voltage
P1634....Ignition power circuit low voltage
P1635....5 volt reference voltage to sensors low
P1636....Powertrain control module fault ( Click Here for help troubleshooting PCM problems)
P1637....Alternator warning lamp control signal "L" terminal problem
P1638....Alternator Field (F) terminal circuit
P1639....Powertrain Control Module 5 volt reference voltage low
P1640....Powertrain control module fault
P1641....EVAP fuel tank pressure sensor circuit voltage high, or fan 1 relay control circuit, or MIL light circuit, or A/C compressor clutch relay circuit (Click Here for help diagnosing EVAP faults)
P1642....Fan control relay, or vehicle speed sensor output, or secondary air injection relay fault (96 Lumina/Monte 3.4L)
P1643....Powertrain control module fault ( Click Here for help troubleshooting PCM problems)
P1644....Throttle position sensor circuit, or traction control fault
P1645....Boost control solenoid circuit, or EVAP solenoid output circuit
P1646....Powertrain control module fault (quad driver 1)
P1647....Powertrain control module fault (quad driver 1)
P1650....Powertrain control module fault (quad driver 2)
P1651....Powertrain control module fault (quad driver 2), or cooling fan relay 1
P1652....Cooling fan relay 2, or suspension control module (Cadillac only)
P1653....Traction control circuit (Pontiac), or fuel gauge control circuit (Chevy except Caprice), or engine oil level warning lamp (Caprice & 99 Olds Silhouette only)
P1654....A/C relay circuit, or cruise control disable output circuit
P1655....Powertrain control module fault (quad driver 2), or EVAP canister purge valve (Click Here for help diagnosing EVAP faults)
P1656....Powertrain control module fault (quad driver 2), or wastegate solenodi control circuit (turbo models only)
P1657....Powertrain control module fault (quad driver 2), or skip shift solenodi control circuit
P1660....Cooling fan circuit,or powertrain control module fault
P1661....EVAP fuel tank pressure sensor circuit, or Check Engine Light circuit, or PCM quad driver fault
P1662....PCM quad driver fault, or cruise control circuit
P1663....Alternator warning lamp circuit, or oil change warning lamp circuit
P1664....Powertrain control modeul fault (quad driver 3), or fuel cutoff solenoid
P1665....Powertrain control module fault (quad driver 3), or EVAP canister vent valve
P1667....Powertrain control module fault (quad driver 3), or reverse inhibit solenoid control circuit
P1670....Powertrain control module fault (quad driver 4)
P1671....Malfunction Indicator Lamp (MIL) circuit fault
P1672....Powertrain control module fault (quad driver 4), or low engine oil level lamp control circuit
P1673....Powertrain control module fault (quad driver 4), or engine hot lamp control circuit
P1674....Powertrain control module fault (quad driver 4), or tachometer control circuit
P1675....EVAP vent solenoid control circuit (Click Here for help diagnosing EVAP faults )
P1676....Powertrain control module fault (quad driver 4), or EVAP canister vent valve
P1677....Powertrain control module fault (quad driver 4)
P1680....Powertrain control module fault ( Click Here for help troubleshooting PCM problems)
P1681....Powertrain control module fault
P1682....Powertrain control module fault
P1683....Powertrain control module fault
P1684....Powertrain control module fault
P1685....Powertrain control module fault
P1686....Powertrain control module fault
P1687....Powertrain control module fault
P1689....Traction Control System delivered torque control circuit
P1690....Powertrain control module loop overrun
P1691....Coolant gauge circuit voltage low
P1692....Coolant gauge circuit voltage high
P1693....Tachometer circuit voltage low
P1694....Tachometer circuit voltage high
P1695....Remote keyless entry circuit
P1696....Remote keyless entry circuit
Click Here for List of GM Codes P1000 to P1299
Click Here for List of GM Codes P1300 to P1499
Click Here for List of GM Codes P1700 to P1899
