P0123

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 control module stores the DTC information into memory when the diagnostic runs and fails.
^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
^ The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC Last Test Failed clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
^ Use a scan tool in order to clear the DTC.

DIAGNOSTIC AIDS
A scan tool reads the APP 1 position in volts. The APP 1 position should read approximately 0.45-0.95 volts with the throttle closed and the ignition ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward Wide Open Throttle (WOT). Also, 90 percent pedal travel is acceptable for correct APP operation. Scan the 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 WOT position. A DTC P0123 will result if the ground circuit is open or if the signal circuit is shorted to voltage.

TEST DESCRIPTION

Steps 1-13:

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 Powertrain Control Module (PCM) and the wiring.