Throttle Position (TP) Sensor & Soft/Hard Closed Throttle Position (CTP) Switch

TP sensor incorporates a potentiometer, which varies output voltage in response to changes in throttle position. This information is relayed to ECM as input voltage signals on 3-terminal TP sensor harness. TP sensor can also inform ECM of opening and closing speeds in throttle valve. Throttle position sensor is attached to throttle body housing and actuated with movement of accelerator pedal.

ECM determines idle position of throttle valve from signals received from TP sensor. This system is called soft closed throttle position switch and it controls engine operation such as fuel cut. When soft closed throttle position switch malfunctions, CTP hard closed throttle position switch signal (throttle valve is in idle position or off idle position), is used for engine control.