P2123

DTC P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage

Wiring Diagram:

Circuit Description
The accelerator pedal assembly contains 2 Accelerator Pedal Position (APP) sensors. The APP sensors are mounted in the pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to the position of the accelerator pedal. The Engine Control Module (ECM) supplies a separate 5 volt reference and low reference circuit for each of the APP sensors. The APP sensor 1 signal voltage increases as the pedal is depressed, from approximately 1.0 V at rest to above 4 V when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 V at rest to more than 2 V with the accelerator pedal fully depressed.

Conditions for Setting the DTC
APP sensor voltage is less than 4.766 V for 3 seconds.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fails. The information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn OFF at the end of a consecutive validation cycle in which the diagnostic runs without a fault.
- A history DTC will clear after 40 warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

Diagnostic Aids
For an intermittent condition, refer to Intermittents. Intermittents

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the internal circuits of the APP sensor 1 throughout its range of motion. If this DTC sets when slowly moving the pedal from the rest position to Wide Open Throttle (WOT), replace the APP assembly for an internal fault.
7. This step tests for high resistance in the low reference circuit of the APP sensor 1. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/Transaxle Control Module (TCM) fuse allows the ECM to power down completely.

Step 1 - 5:

Step 6 - 16:

DTC Troubleshooting