P0117 GMC Engine Coolant Temperature Circuit Low Input

Possible causes – Low engine coolant level– Faulty Engine Coolant Temperature (ECT) sensor– Faulty engine coolant thermostat– Engine Coolant Temperature (ECT) sensor harness is open or shorted– Engine Coolant Temperature (ECT) sensor circuit poor electrical connection When is the obd code mean? An excessively low voltage from the sensor is sent to ECM. Symptoms –…

P0118 GMC Engine Coolant Temperature Circuit High Input

Possible causes – Low engine coolant level– Faulty Engine Coolant Temperature (ECT) sensor– Faulty engine coolant thermostat– Engine Coolant Temperature (ECT) sensor harness is open or shorted– Engine Coolant Temperature (ECT) sensor electrical circuit poor connection When is the obd code mean? When the Powertrain Control Module (PCM) senses a signal voltage higher than the…

P0125 GMC Insufficient Coolant Temperature for Closed Loop Fuel Control

Possible causes – Low engine coolant level– Leaking or stuck open thermostat– Faulty Engine Coolant Temperature (ECT) sensor– Engine Coolant Temperature (ECT) sensor harness is open or shorted– Engine Coolant Temperature (ECT) sensor electrical circuit poor connection When is the obd code mean? The voltage sent to Powertrain Control Module (PCM) from the Engine Coolant…

P0521 GMC Engine Oil Pressure Sensor/Switch Circuit Range/Performance

Possible causes – Low oil level or motor mechanical fault– Faulty oil pressure sensor– Oil Pressure Sensor harness is open or shorted– Oil Pressure Sensor circuit poor electrical connection When is the obd code mean? The P0521 is detected when the signal sent from oil pressure sensor to PCM goes out of range. Symptoms –…

P1396 GMC Wheel Speed Sensor Circuit

Possible causes – Faulty Wheel Speed Sensor– Wheel Speed Sensor harness is open or shorted– Wheel Speed Sensor circuit poor electrical connection When is the obd code mean? The Engine Control Module (ECM) detects an invalid rough road signal from the wheel speed sensor. P1396 GMC OBD Code Description The road situation is estimated with…

P1681 GMC Control Module Not Programmed

Possible causes – Fualty ECM– Wrong ECM for vehicle– Service program error When is the obd code mean? Engine Control Module (ECM) program does not recognize the vehicles id, or the id is missing in the ECM. Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1681 GMC OBD Code Description This diagnostic…

P0052 GMC HO2S Heater Control Circuit High Bank 2 Sensor 1

Possible causes – Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 harness is open shorted to ground– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit poor electrical connection– Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit fuse– Faulty Engine Control Module (ECM) When is…

P2178 GMC Fuel Trim System Rich at Cruise or Accel

Possible causes – High fuel pressure– Leaking fuel injector or pressure regulator– Failed Mass Air Flow (MAF) sensor When is the obd code mean? The Engine Control Module (ECM) has detected a rich air/fuel ratio Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P2178 GMC OBD Code Description The Engine Control Module…

P1508 GMC Idle Speed Low Idle Air Control System Not Responding

Possible causes – Idle Air Control Valve harness is open or shorted– Idle Air Control Valve circuit poor electrical connection– Faulty Idle Air Control Valve Symptoms – Engine Light ON (or Service Engine Soon Warning Light)– Engine rough idle

P0410 GMC Secondary Air Injection System Malfunction

Possible causes – Faulty Vacuum hoses damaged– Faulty Air Pump inoperative– Air bypass solenoid harness is open or shorted– Air bypass solenoid circuit poor electrical connection– Air bypass solenoid leaking/blocked or stuck open/closed– Air diverter valve leaking/blocked or stuck open/closed Tech description Visually inspect AIR pump and AIR bypass valve harness and connector, if connector…