Throttle Position Sensor (TPS) & Idle Switch

TPS incorporates a potentiometer, which varies output voltage in response to changes in throttle position. This information is relayed to ECU as input voltage signals on 3-terminal TPS harness. TPS also has ability to inform ECU of rate of speed changes taking place in throttle plate movement. It is attached to throttle body housing and actuated with movement of accelerator pedal.

Idle switch, which is an integral part of TPS, is closed at idle and open during all other conditions. Switch signal is used in event of TPS failure to inform ECU when throttle is closed for fuel cut on deceleration.