P0405 GMC Exhaust Gas Recirculation Position Sensor Circuit Low Voltage

Possible causes – Faulty EGR volume control solenoid valve– EGR volume control solenoid valve harness is open or shorted– EGR volume control solenoid valve circuit poor electrical connection– EGR temperature sensor and circuit When is the obd code mean? An improper voltage signal is sent to Powertrain Control Module (PCM) through the valve Symptoms –…

P2135 GMC Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation

Possible causes – Faulty electric throttle control actuator (TP sensor 1 and 2)– Throttle Position Sensor harness is open or shorted– Throttle Position Sensor circuit poor connection– Faulty accelerator pedal position sensor Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P2135 GMC OBD Code Description

U0100 GMC Lost Communication With Engine Control Module

Possible causes – Faulty Engine Control Module (ECM)– ECM harness is open or shorted– ECM circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light) U0100 GMC OBD Code Description

P0641 GMC 5 Volt Reference Voltage Incorrect

Possible causes – Faulty Engine Control Module (ECM)– ECM harness is open or shorted– ECM circuit poor electrical connection– Shorted sensor on 5 volt circuit When is the obd code mean? The Engine Control Module (ECM) has detected the sensor 5 volt reference circuit voltage is higher or lower than expected Symptoms – Engine Light…

P0651 GMC 5 Volt Sensor Reference 2 Circuit

Possible causes – Faulty Engine Control Module (ECM)– ECM harness is open or shorted– ECM circuit poor electrical connection– Shorted sensor on 5 volt circuit When is the obd code mean? The Engine Control Module (ECM) has detected the sensor 5 volt reference circuit voltage is higher or lower than expected Symptoms – Engine Light…

P0676 GMC Cylinder 6 Glow Plug Circuit Fault

Possible causes – Faulty cylinder #6 glow plug– Cylinder #6 glow plug harness is open or shroted– Cylinder #6 glow plug circuit poor electrical connection– Faulty glow plug module When is the obd code mean? The Engine Control Module (ECM) has detected a fault in the cylinder #6 glow plug circuit Symptoms – Engine Light…

P0677 GMC Cylinder 7 Glow Plug Circuit Fault

Possible causes – Faulty cylinder #7 glow plug– Cylinder #7 glow plug harness is open or shroted– Cylinder #7 glow plug circuit poor electrical connection– Faulty glow plug module When is the obd code mean? The Engine Control Module (ECM) has detected a fault in the cylinder #7 glow plug circuit Symptoms – Engine Light…

P0678 GMC Cylinder 8 Glow Plug Circuit Fault

Possible causes – Faulty cylinder #8 glow plug– Cylinder #8 glow plug harness is open or shroted– Cylinder #8 glow plug circuit poor electrical connection– Faulty glow plug module When is the obd code mean? The Engine Control Module (ECM) has detected a fault in the cylinder #8 glow plug circuit Symptoms – Engine Light…

P3400 GMC Cylinder Deactivation System Performance

Possible causes – Faulty Cylinder Deactivation Solenoid– Cylinder Deactivation Solenoid harness is open or shorted– Cylinder Deactivation Solenoid circuit poor electrical connection When is the obd code mean? The control module detects that the actual measured values from the MAF sensor, MAP sensor, and TP sensor, is not within the range of the calculated values…