P1639 OBD Code Definition:
P1639 Throttle Valve Position Control; Throttle Stuck Permanently
P1639 OBD Code Description:

Possible Symptoms

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

Possible Causes

• Wiring and/or connections faulty
• 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 ECM to Accelerator Pedal

Special Notes

• There are 2 sensors in the accelerator pedal, both should increase in the same direction as the accelerator is pressed but they have different scales. This means one counts from 0 to 100, while the other one counts from 0 to 50.

• 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.