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 outputs such as fuel injection quantity, pressure regulator solenoid valve control and A/C cut-off.

ECU reference voltage is approximately 0.5V at idle and 4.3V at wide open throttle.