P0121 GMC Throttle Position Sensor 1 Performance

Possible causes – Throttle position sensor harness is open or shorted– Throttle position sensor circuit poor electrical connection– Faulty throttle position sensor.– Faulty Engine Control Module (ECM) When is the obd code mean? Malfunction is detected when an excessively low or high voltage from the sensor is sent to ECM. Symptoms – Engine Light ON…