Throttle Position Sensor: Testing and Inspection

A Tech 1 scan tool displays throttle position in volts. The 3.1L should read under 1.25 volts, with throttle closed and ignition "ON," or at idle. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).

The Powertrain Control Module (PCM) has the ability to auto-zero the Throttle Position (TP) sensor voltage, if it is below about 1.25 volts. This means that any voltage less than 1.25 volts will be determined by the PCM to be 0% throttle. Some scan tools have the ability to read the percentage of throttle angle and should read 0%, when the throttle is closed. A failure in the TP sensor or circuit should set a DTC 21 or 22.