For 1990-2009 cars

The throttle position (TP) sensor is a potentiometer that varies resistance according to changes in throttle plate position. The powertrain control module (PCM) measures the signal voltage from the TP sensor which is a reduced value of the PCM 5-volt reference. The voltage ranges from 0.4 (+/-0.2) volts at 0% throttle to 4.7 (+/-0.2) volts at wide open throttle. DTC P0123 sets when the TP sensor signal voltage at the PCM is above the calibrated voltage value.

### DTC Parameters

DTC P0123 will set if TP sensor voltage is greater than 4.9 volts when:

• | The condition exists for longer than 10 seconds.

• | The ignition is ON.

DTC P0123 diagnostic runs continuously with ignition ON.

DTC P0123 is a type A DTC.

### Diagnostic Aids

Important: If DTC P1635 is set, diagnose that DTC first.

To locate an intermittent problem, use a scan tool to monitor TP SENSOR voltage with ignition ON, engine OFF. Wiggling the wires while watching for a change in TP SENSOR voltage may locate the area where an open or short to voltage in the wiring could lie.

An intermittent short in the TP SENSOR can cause this DTC to set. Use scan tool to monitor the TP SENSOR as the accelerator pedal is slowly depressed. The voltage should change smoothly from 0.4 volts at 0% throttle, to 4.7 volts at wide open throttle (+/-0.2 volts).