Throttle Position Sensor

The Throttle Position (TP) sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, low reference circuit and a signal circuit. This provides the PCM with a signal voltage proportional to throttle plate movement. TP sensor 1 signal voltage at closed throttle is about 5-volt reference and decreases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is about low reference and increases as the throttle plate is opened. When TP sensor 1 signal voltage is not within the predicted range, a DTC sets. To diagnose, ee SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article.