P0123

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The Accelerator Pedal Position (APP) module provides a voltage signal that changes relative to the accelerator pedal position. There are 3 sensors located within the APP module that are scaled differently.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
^ The voltage is more than 4.75 volts on the APP 1 sensor.
^ The condition was 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 stores in the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other emissions related diagnostic.
^ Use a scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS
A scan tool reads the APP 1 position in volts. It should read approximately 0.45-0.95 volts 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 APP operation. Scan APP 1 sensor while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from approximately 0.74 volts when the throttle is closed to approximately 3.7 volts when the throttle is held at the Wide Open Throttle (WOT) position. A P0123 will result if the ground circuit is open or if the signal circuit is shorted to voltage.

TEST DESCRIPTION
The numbers below refer to the step numbers 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 the wiring.