Throttle Position Sensor: Testing and Inspection

Throttle Position Sensor

A scan tool displays Throttle Position (TP) in volts. The scan tool should display 0.20 volt to 0.90 volt with the throttle closed (as at idle) and ignition ON. Voltage should increase at a steady rate as the throttle opens. Voltage should be near 5.0 volts at wide open throttle.

A scan tool also has the ability to display the throttle angle and should display 0% when the throttle is closed, and increase smoothly to 100% at Wide Open Throttle (WOT). The Powertrain Control Module (PCM) has the ability to auto-zero the TP sensor voltage if it is below about 0.90 volt (900 mV). This means that any voltage less than 0.90 volt will be determined by the PCM to be 0% throttle.

Circuit Faults

A fault in the TP sensor or circuit should set either a DTC P0122 or DTC P0121. A stuck sensor will set a DTC P0121.