From Ross-Tech Wiki

18039/P1631 - Accelerator Position Sensor (G79): Signal too High

Possible Symptoms

  • Malfunction Indicator Light (MIL) ON
  • Reduced Engine Output

Possible Causes

  • Wiring Harness from Accelerator Pedal to ECM
  • Faulty ECM
  • Faulty Accelerator Pedal

Possible Solutions

  • Check Measuring Block Readings for Accelerator Pedal
  • Check Voltage Signals from ECM to Throttle Pedal (see factory repair manual)
  • Check Wiring and Connectors from Accelerator Pedal to ECM

Special Notes

  • Accelerator Position Sensor faults can be caused by issues with the Oxygen Sensor(s) and it's wiring. Please verify this BEFORE replacing the ECM or Accelerator Pedal. Accelerator Pedal failure is very rare.