DTC P0121 - TP SENSOR SYSTEM PERFORMANCE Pontiac Firebird IV

Note. For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .

Circuit Description

Throttle Position (TP) sensor measures amount of throttle opening. PCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle.

Conditions required to set DTC are

1. Engine running and throttle steady.
2. No MAP or TP sensor DTCs are set
3. Predicted throttle angle not close to actual throttle angle.
4. Conditions present greater than 10 seconds.