Vibe FWD L4-1.8L VIN 8 (2004)
Throttle Position Sensor: Description and Operation
THROTTLE POSITION (TP) SENSOR
The throttle position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body. By monitoring the voltage on the signal line, the
powertrain control module (PCM) calculates the throttle position. As the throttle valve angle changes when the accelerator pedal is moved, the TP sensor
signal also changes. At a closed throttle position, the output of the TP sensor is low. As the throttle valve opens, the output increases so that at wide open
throttle, the output voltage should be more than 3.3 volts.
Because the position of the throttle valve controls the air supply to the engine, the PCM can modify the fuel delivery based on the throttle angle. For
example, power enrichment occurs when the throttle angle approaches wide-open throttle. The PCM looks primarily for changes in the TP sensor output
to control fuel delivery. Acceleration enrichment occurs when the throttle angle increases, similar to the accelerator pump on a carburetor equipped
vehicle.
