P1271 GMC Accelerator Pedal Position Sensor 1-2 Correlation

Possible causes – Accelerator Pedal Position Sensor 1-2 harness is open or shorted – Accelerator Pedal Position Sensor 1-2)circuit poor electrcila connection – Faulty Accelerator Pedal Position Sensor 1-2 Symptoms – Engine Light ON (or Service Engine Soon Warning Light) – Possible poor acceleration P1271 GMC OBD Code Description

P0068 GMC MAP/MAF – Throttle Position Correlation

Possible causes – Air leak between the MAF sensor and throttle body– Dirty Throttle body or Mass Air Flow (MAF) sensor– Throttle Position (TP) sensor not seated properly– Faulty Throttle Position (TP) sensor– Faulty Mass Air Flow (MAF) sensor When is the obd code mean? If the PCM detects that the difference between the actual…

P0621 GMC Generator Lamp L Control Circuit Malfunction

Possible causes – Battery charge– Faulty Generator– Generator harness is open or shorted– Generator circuit poor electrical connection– Engine Control Module (ECM) controlled generator– Faulty ECM Tech description The ECM is detecting a high turn-on voltage at times. Possible causes could be the alternator or the ECM. When is the obd code mean? The Engine…

P0620 GMC Generator Performance Condition

Possible causes – Battery charge– Faulty Generator– Generator harness is open or shorted– Generator circuit poor electrical connection– Engine Control Module (ECM) controlled generator– Faulty ECM When is the obd code mean? The Engine Control Module (ECM) has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault…

P0563 GMC System Voltage High

Possible causes – Battery defective– Loose or missing alternator drive belt– Faulty alternator– Open or short system voltage circuit Tech description Higher than expected voltage problems are most likely caused by bad voltage regulator. The voltage regulator is part of the alternator. When is the obd code mean? The Powertrain Control Module (PCM) has detected…

P0526 GMC Cooling Fan Speed Sensor Circuit

Possible causes – Cooling fan harness and connector– Faulty cooling fan When is the obd code mean? The P0526 code is detected when the PCM has detected a loss of cooling fan speed signal and the condition is present for at least 11 seconds. Symptoms – Engine Light ON (or Service Engine Soon Warning Light)–…

P1635 GMC 5 Volt Reference Circuit

Possible causes – A/C Pressure sensor harness is open or shorted– MAP sensor harness is open or shorted– EGR valve harness is open or shorted When is the obd code mean? The P1635 code is set when the reference voltage from the sensor is our of range. Symptoms – Engine Light ON (or Service Engine…

P0532 GMC A/C Refrigerant Pressure Sensor Circuit Low Input

Possible causes – A/C system low or over charge with refrigerant– Faulty A/C refrigerant pressure sensor– Cooling fans in-operative– A/C refrigerant pressure sensor circuit open or shorted– A/C refrigerant pressure sensor circuit poor electrical connection When is the obd code mean? The P0532 code is detected when the signal circuit is too low. Symptoms –…

P0533 GMC A/C Refrigerant Pressure Sensor Circuit High Input

Possible causes – A/C system low or over charge with refrigerant– Faulty A/C refrigerant pressure sensor– Cooling fans in-operative– A/C refrigerant pressure sensor circuit open or shorted– A/C refrigerant pressure sensor circuit poor electrical connection When is the obd code mean? The P0533 code is detected when the signal circuit is too high. Symptoms –…