Throttle Position Sensor: Description and Operation

Voltage Versus Throttle Position Chart:

The Throttle Position (TP) sensor is a potentiometer used to indicate the amount of throttle opening. The PCM supplies the TP sensor with a 5 volt reference and a ground. The TP sensor provides a signal voltage to the PCM relative to throttle blade angle. By monitoring the voltage on the signal line, the PCM calculates throttle position. As the throttle valve changes (accelerator pedal moves), the TP sensor output voltage will change. With the throttle closed, the signal voltage is low (below 1 volt). However,the TP sensor voltage increases as the throttle valve opens. At Wide Open Throttle (WOT), the TP sensor voltage should be above 4 volts.

The TP signal is one of the most important sensor inputs used by the PCM for controlling fuel and most of the PCM-controlled outputs. A malfunction in the TP sensor or related wiring should set DTC P0122 or DTC P0123. An intermittent condition will set DTC P1121 or DTC P1122. If the actual TP sensor signal does not match a PCM calculated TP value, DTC P0121 will set.