P0123

DTC P0123 App Sensor 1 Circuit High Voltage






Circuit Description

The Accelerator Pedal Position (APP) module provides a voltage signal that changes relative to the accelerator pedal position. There are three sensors located within the APP module that are scaled differently.

Conditions for Running the DTC

The ignition switch in the on position.

Conditions for Setting the DTC

^ The voltage is greater than 4.75 volts on APP 1 sensor.
^ All diagnostic set conditions met for 2 seconds.

Action Taken When the DTC Sets

^ The service throttle soon lamp will not illuminate when one APP DTC sets. The PCM will only illuminate the service throttle soon lamp when multiple APP DTCs set.
^ The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Failure Records.

Conditions for Clearing the MIL/DTC

^ A History DTC will clear after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use of a scan tool will clear the DTC codes.

Diagnostic Aids

A scan tool reads APP 1 position in volts. It should read about 0.45 to 0.95 volt with the throttle closed and the ignition ON or at idle. Voltage should increase at a steady rate as the throttle is moved toward wide open throttle (WOT). Also, 90% pedal travel is acceptable for correct 0 APP operation. Scan the APP 1 sensor while depressing the accelerator pedal with the engine stopped and the ignition ON. Display should vary from about 0.74 volt when the throttle is closed to about 3.7 volt when throttle is held at wide open throttle (WOT) position. A P0123 will result if the ground circuit is open or the signal circuit is shorted to voltage.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. This step determines if DTC P0123 is the result of a hard failure or an intermittent condition.
3. This step checks the PCM and wiring.