Throttle Position Sensor: Description and Operation

Throttle Position Sensor:

PURPOSE
The Engine Control Module (ECM) controls fuel injection based on the input signal from the Throttle Position Sensor (TPS).

OPERATION
- The ECM supplies a 5 volt reference and a ground for the sensor.
- As the throttle shaft rotates, the voltage drop across the TPS changes.
- As the throttle valve shaft rotates from the idle position to wide open position the resistance between the variable resistor terminal of the throttle position sensor and the ground terminal increases. As a result the voltage at the throttle position sensor variable resistance terminal also increases.
- The ECM determines the throttle valve opening based on the output voltage.
- The ECM computes throttle valve opening change (output voltage change) and judges the engine acceleration state and accordingly corrects fuel injection amount during acceleration.