Enhance Testing

P0121 - Throttle Position Sensor Circuit Range/Performance Problem






General Description
Throttle Position (TP) Sensor measures the opening angle of throttle valve and mounted on the side of the throttle body and is connected to the throttle blade shaft. The TP sensor's resistance changes according to the throttle blade shaft position. TP Sensor has a potentiometer whose resistance changes along with the Throttle valve position. The Powertrain Control Module (ECM) provides a 5volt reference voltage to the TP Sensor. The ECM reads the voltage across the TP Sensor and converts it into throttle position. During acceleration, the TP Sensor resistance decreases. During deceleration, the TP Sensor resistance increases. The ECM uses the TP Sensor signal to adjust timing and injector pulse width. The TP Sensor signal along with the MAF sensor signal is used by the ECM to calculate engine load. Throttle angle information to the ECM to be used for the detection of engine status such as idle, part load, full throttle, and acceleration fuel enrichment.

DTC Description
If the sensor output voltage is out of threshold value, the ECM determines that a malfunction exists and a DTC is stored.

Detecting Condition and Specifications





Wiring Schematic





Signal Waveform