Throttle Position Sensor (TPS) & Idle Switch

The TPS has a potentiometer which varies output voltage in response to changes in throttle position. This information is relayed to the ECU in the form of an input voltage signal on the 3-terminal TPS harness. See Figure . The TPS also has the ability to inform the ECU of the rate of changes taking place in throttle plate movement. TPS is attached to throttle body housing and is actuated by movement of the accelerator pedal.

The idle switch is an integral part of the TPS. Switch is closed at idle and open during all other conditions. Switch is used to inform the ECU when the throttle is closed for fuel-cut on deceleration. Switch also has a full throttle position used only on vehicles equipped with an automatic transmission control unit.