Throttle Position Sensor: Description and Operation

Throttle Position Sensor:

The Throttle Position Sensor (TPS) consists of a contact point (idle switch) and a potentiometer. The TPS is connected to the throttle valve shaft on the throttle body, and detects the throttle valve opening. The throttle opening in the idle state is detected by means of the idle switch which supplies B+ to the ECM when the throttle is moved off idle. The full opening is detected by the potentiometer. A 5-volt reference voltage is applied to the sensor from the ECM and the resistance varies according to the throttle valve opening, the output voltage varies accordingly. By monitoring the sensor output voltage, the ECM detects the throttle valve opening and its change.