DTC P021: Shorted Throttle Position (TP) Sensor: Description

The Throttle Position (TP) Sensor is a potentiometer. A 5 volt reference is provided on CKT 474 and ground is provided on CKT 476. The TPS signal CKT 417 varies between ground and 5 volts based on the position of the throttle plates. At low throttle angle, the TP sensor signal voltage is low. The PCM uses TP sensor information to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. Code P021 sets when the PCM detects a TP sensor signal that is too high.