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.
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.
P1031....O2 Sensor heater control circuit problem
P1105....Secondary Vacuum Sensor circuit
P1106....MAP sensor circuit voltage intermittent high or low Click Here for help diagnosing MAP Sensor faults
P1107....MAP sensor voltage intermittent low
P1108....BARO to MAP sensor circuit comparison too high
P1109....Secondary port throttle system
P1111....Intake Air Temperature Sensor circuit intermittent high voltage Click Here for help diagnosing Air Temperature Sensor faults
P1112....Intake Air Temperature Sensor circuit intermittent low voltage
P1113....Intake Resonance Switchover Valve Control
P1114....Engine Coolant Temperature intermittent high or low Click Here for help diagnosing coolant sensor faults
P1115....Engine Coolant Temperature intermittent high or low
P1116....Engine Coolant Temperature erratic
P1117....Engine coolant temperature below minimum voltage/254 F
P1118....Engine coolant temperature above maximum voltage/-40 F
P1119....Engine coolant temperature out of range
P1120....Throttle position sensor 1 circuit Click Here for help diagnosing TPS sensor faults
P1121....Ignition control module 4X circuit, or TPS out of range
P1122....Ignition control module 4X circuit, or TPS out of range
P1125....Average Pump Period system, or pedal position system
P1133....A/C pressure sensor high voltage, or O2 sensor bank 1 sensor 1 sluggish
P1134.... 5 volt reference 2 voltage low, or O2 sensor bank 1 sensor 1
P1135....O2 Sensor 1 bank 1 reading lean, or 4/5 shift solenoid stuck on
P1136....5 volt reference 2 circuit, or O2 sensor bank 1 sensor 1 rich
P1137....O2 Sensor low voltage during power enrichment
P1138....O2 Sensor high voltage during decel fuel cutoff
P1139....Brake booster vacuum sensor (low vacuum)
P1139. . O2 Sensor insufficient switching (Bank 1 Sensor 2) Click Here for help diagnosing Oxygen Sensor faults
P1140....O2 Sensor Sluggish (Bank 1 Sensor 2)
P1141....O2 Sensor Heater Control circuit (Bank 1 Sensor 2)
P1143....O2 Sensor reading lean or low voltage (Bank 1 Sensor 3)
P1144....O2 Sensor reading rich or high voltage (Bank 1 Sensor 3)
P1145....O2 Sensor sluggish (slow crosscounts) (Bank 1 Sensor 3)
P1153....A/C pressure sensor low voltage
P1154.... O2 Sensor low switching (Bank 2 Sensor 1) Click Here for help diagnosing Oxygen Sensor faults
P1155....A/C evap temperature switch high voltage
P1155. . O2 Sensor reading lean (Bank 2 Sensor 1)
P1156....A/C high pressure switch high voltage
P1156. . O2 Sensor reading rich (Bank 2 Sensor 1)
P1157....O2 Sensor rich or high voltage (Bank 2 Sensor 2)
P1158....O2 Sensor rich or high voltage (Bank 2 Sensor 2)
P1158. . .Engine overtemperature protection fault Click Here for help troubleshooting causes of Engine Overheating
P1159....O2 Sensor crosscounts (Bank 2 Sensor 2)
P1161....O2 Sensor heater control circuit (Bank 2 Sensor 2)
P1163....O2 Sensor reading lean or low voltage (Bank 2 Sensor 3)
P1164....O2 Sensor reading rich or high voltage (Bank 2 Sensor 3)
P1165....O2 Sensor crosscounts (Bank 2 Sensor 3)
P1170....Bank to bank fuel trim offset
P1171....Fuel system lean during acceleration
P1185....Engine Temperature Sensor circuit
P1186....Engine Oil Temperature circuit performance
P1187....Engine Oil Pressure Sensor circuit low voltage Click Here for help diagnosing low oil pressure problems
P1188....Engine Oil Pressure Sensor circuit voltage high
P1189....Engine Oil Pressure Switch circuit
P1190....Vacuum leak Click Here for help diagnosing & finding vacuum leaks
P1191....Intake air duct leak
P1200....Injector control circuit
P1211....Mass Airflow circuit intermittent high Click Here for help diagnosing Airflow Sensor faults
P1212....Mass Airflow circuit intermittent low
P1214....Injection Pump Timing Offset
P1215....Ground fault detection indicated (generator driver circuit)
P1216....Fuel Solenoid response time too short
P1217....Fuel Solenoid response time too long
P1218....Injection Pump calibration circuit
P1219....Throttle Position Sensor reference voltage Click Here for help diagnosing TPS Sensor faults
P1220....Throttle Position Sensor circuit fault
P1221....Fuel pump second circuit low
P1121. . Throttle position sensor circuit performance
P1222....Injector circuit cylinder 1 intermittent
P1225....Injector circuit cylinder 2 intermittent
P1228....Injector circuit cylinder 3 intermittent
P1231....Injector circuit cylinder 4 intermittent
P1234....Injector circuit cylinder 5 intermittent
P1237....Injector circuit cylinder 6 intermittent
P1240....Injector circuit cylinder 7 intermittent
P1243....Injector circuit cylinder 8 intermittent
P1250....Early fuel evaporation heater circuit
P1257....Boost Control fault, or supercharger overboost
P1258....Engine overtemperature protection, or low coolant fuel disable
P1260....Fuel Pump Speed Relay control circuit, or last test failed speed control circuit
P1271....Accelerator Pedal Position Sensor 1-2 correlation ( Click Here for help troubleshooting Electronic Throttle Control problems)
P1272....Accelerator Pedal Position Sensor 2-3 correlation
P1273....Accelerator Pedal Position Sensor 1-3 correlation
P1274....Injection wiring incorrect
P1275....Acceleration position sensor 2 circuit, or boost control
P1276....Accelerator Pedal Positioning Sensor 1 circuit
P1280....Accelerator Pedal Positioning Sensor 2 circuit
P1281....Accelerator Pedal Positioning Sensor 2 circuit out of range
P1285....Accelerator Pedal Positioning Sensor 2 circuit
P1286....Accelerator Pedal Positioning Sensor 2 circuit out of range
Click Here for List of GM Codes P1300 to P1499
Click Here for List of GM Codes P1500 to P1699
Click Here for List of GM Codes P1700 to P1899