Throttle Position Sensor: Description and Operation

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 PCM calculates throttle position. As the throttle valve angle is changed (accelerator pedal 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 TP sensor voltage increases so that at Wide Open Throttle (WOT), the TP sensor voltage should be above 4 volts. The PCM calculates fuel delivery based on throttle valve angle (driver demand).