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Throttle Position Sensor

The Throttle Position (TP) sensor, located on top of the engine, on the lower front of the throttle body, is used by the Powertrain Control Module (PCM) to determine the throttle plate angle for various engine management systems. See Fig 1 . The TP sensor is a potentiometer type sensor with 3 circuits:

The PCM provides the TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from the closed throttle position to the Wide Open Throttle (WOT) position provides the PCM with a signal voltage from less than one volt to more than 4 volts through the TP sensor signal circuit. If the PCM detects an signal voltage out of predicted range a DTC will set.

Fig 1: Locating TP Sensor, EGR & IAC Valve
G00028314Courtesy of GENERAL MOTORS CORP.