Throttle Position Sensor: Description and Operation

Throttle Sensor:

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. ECU reference voltage is approximately 0.3V at idle and 4.0V at wide open throttle.

An Idle Switch is incorporated into the throttle sensor assembly. It is an "ON/OFF" switch utilized by the ECU to determine when the throttle is fully closed.

Throttle sensor and idle switch inputs are used by the ECU in calculations for these outputs:

Fuel injection quantity
Pressure regulator control
Idle speed
Purge control solenoid valve
A/C cut-off