Throttle Position Sensor: Description and Operation

Throttle Position Sensor (TPS) Operation:

The Throttle Position Sensor (TPS) 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. A 5-volt reference voltage is applied to the sensor from the 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. The ECM uses the signal from the TPS as one of the signals to control (fuel injector, ISC solenoid valve and EGR VSV (if equipped). Also, the ECM converts the voltage signal from the TPS into "ON/OFF" signal and sends it to Transmission Control Module (TCM), where it is used as one of the signals to control the automatic transmission.