Throttle Position Sensor: Description and Operation

Throttle Sensor:

PURPOSE
Signals throttle open/closed position to the ECU.

LOCATION
Side of throttle body.

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 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 idle speed control. Integral with the sensor is an idle switch. The ECU monitors this switch to detect when the throttle valve is closed.