P2138

DTC P2138

Circuit Description

The accelerator pedal position (APP) sensors 1 and 2 are located within the accelerator pedal assembly. Each sensor has the following circuits:

* A 5-volt reference circuit
* A low reference circuit
* A signal circuit

This provides the powertrain control module (PCM) with a signal voltage proportional to accelerator pedal movement. The APP sensor 1 signal voltage at rest position is near the low reference and increases as the pedal is actuated. The APP sensor 2 signal voltage at rest position is near the 5-volt reference and decreases as the pedal is actuated.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation

Conditions for Running the DTC

* The battery voltage is more than 5.23 volts.
* DTCs P0641, P0651, P2120, or P2125, are not set.
* DTC P2138 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for more than 0.5 second.

Action Taken When the DTC Sets

* The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
* The control module commands the TAC system to operate in the Reduced Engine Power mode.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions the control module commands the engine OFF.

Conditions for Clearing the MIL/DTC

* The PCM turns OFF the MIL after 3 consecutive drive trips that the diagnostic runs and does not fail.
* A History DTC clears after 40 consecutive warm up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic.
* The scan tool clears the MIL/DTC.

Diagnostic Aids

* The PCM compares the signal of each of the accelerator pedal position sensor to each other throughout the entire range of operation. Clear the DTCs and actuate the pedal through the entire range with the ignition ON and the engine OFF.
* Use the J 35616 Connector Test Adapter Kit for any test that requires probing the PCM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.
* Refer to Intermittent Conditions for intermittent conditions. Intermittent Conditions

Test Description

Step 1 - Step 8:

The number below refers to the step number on the diagnostic table.
2. Any circuit faults on either APP sensor 1 or 2 will set one of the DTCs listed. Refer to the appropriate table for diagnosis.