Throttle Position Sensor: Description and Operation

Throttle Position Sensor:

Notice: Numbers in text correspond to numbered components in image.

DESCRIPTION
The Throttle Position (TP) sensor is a potentiometer. The TP sensor (2) [electrical connector (1)] mounts on the side of the throttle body. The TP sensor provides a voltage signal that changes relative to the throttle blade angle. This signal voltage is one of the most important inputs that is used by the ECM. The TP sensor has a 5.0 volt reference, a ground and a signal circuit. The signal circuit is pulled up to 5 volts within the ECM.

OPERATION
The ECM calculates the fuel delivery based on the throttle angle (driver demand). A broken or loose TP sensor may cause intermittent bursts of fuel from an injector. This may cause an unstable idle because the ECM detects the throttle is moving. When the ECM detects a malfunction with the TP sensor circuit, the DTC P0120 - TP Sensor Circuit will set.