Code P021, Shorted Throttle Position (TP) Sensor Circuit: Action

PCM turns on MIL, disables TCC and transaxle pressure control. PCM sets TP sensor equal to 13 degrees when TP sensor is open and 6 degrees when TP sensor is closed. PCM disables 3rd and 4th gear.

1. If TP sensor or wiring is shorted, data parameter PD01 will read 87 degrees or greater.
2. Check for shorted TP sensor or wiring if data value stays greater than -3 degrees. An open in circuit No. 808 will cause TP sensor signal to be always high whenever TP sensor is connected.

Fig 1: Code P021 Schematic (DeVille)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P021 Flow Chart (DeVille)

Courtesy of GENERAL MOTORS CORP.