Throttle Position Sensor: Description and Operation

The Throttle 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 the reference voltage supplied by the ECU, allowing it to read throttle valve opening angle. This input is used in ECU calculations for these outputs:

Fuel injection quantity and timing
Idle speed control
EGR vent and vacuum solenoid valves
Pressure regulator solenoid valve
Purge control
Ignition timing control