Throttle Position Sensor

The throttle position sensor is mounted to the throttle body and connected to the throttle plate shaft. The throttle position is a potentiometer with a five volt reference input and a signal ground supplied by the PCM. A sensor output signal to the PCM is a DC signal that varies according to throttle position angle. As the throttle angle changes the signal to the PCM varies.

The throttle position sensor is used in conjunction with other engine sensors to provide inputs to the PCM in order to control a 14.7 to 1 air/fuel ratio under all throttle positions.

At a closed throttle position, the output of the throttle position sensor is low (approximately 0.35 volt). As the throttle plate opens, the output signal increases so that, at wide-open throttle, the output voltage will be high (over 4.65 volts).

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. A fault in the TP sensor or circuit should set a DTC P0122 or P0123.