Throttle Position Sensor: Description and Operation

PURPOSE
Provides Powertrain Control Module (PCM) with signal related to throttle open angle.

OPERATION
Sensor is a potentiometer attached to the throttle body and splined to the throttle shaft. The potentiometer rotates with the shaft as the throttle opens and closes. Varying potentiometer resistance alters reference voltage supplied by the PCM, allowing it to read throttle valve opening angle. This input is used in PCM calculations for fuel injection quantity and timing, fuel pump control, purge control, A/C cut-off, and ignition timing control.