Throttle Position Sensor: Description and Operation

Description:

DESCRIPTION
The Throttle Position (TP) sensor, consisting of a contact point (idle switch) and a potentiometer, 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 contact point which turns "ON" in that state. But beyond that, the full opening is detected by the potentiometer as follows.

OPERATION
A 5 volt reference voltage is applied to the sensor from the Engine Control Module (ECM), and, as its brush moves over the resistance according to the throttle valve opening, the output voltage varies accordingly.

By monitoring the "ON/OFF" signal and sensor output voltage, the ECM detects the throttle valve opening.