P2138

DTC P2138

CIRCUIT DESCRIPTION
The DTC P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation diagnostic monitors the APP sensor 1 signal circuit. The accelerator pedal assembly contains 2 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 powertrain control module (PCM) 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 0.75 volt at rest to about 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 1.6 volts at rest to more than 4.8 volts with the accelerator pedal fully depressed.

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 ignition is ON or the engine is running.
- DTC P2138 runs continuously once the above condition has been met.

CONDITIONS FOR SETTING THE DTC
One or more of the following conditions are present:
- The difference between the APP sensor 1 signal and the APP sensor 2 signal is less than 0.2 volt for at least 2 seconds.
- The APP sensor 1 input to the PCM is less than 0.2 volt for at least 2 seconds.
- The APP sensor 2 input to the PCM is less than 0.5 volt for at least 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL).
- The PCM stores the conditions that were present when the DTC set as Freeze Frame data.
- The engine will operate in the reduced power mode and the APP sensor angle will default to idle.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM turns OFF the MIL on the third consecutive trip in which the diagnostic runs without a fault.
- The PCM clears a History DTC after 40 consecutive warm-up cycles without a fault.
- You use the scan tool Clear DTC Information function.

TEST DESCRIPTION

Step 1 - Step 10:

Step 11 - Step 16:

The numbers below refer to the step numbers on the diagnostic table.
1. The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. If there are any other APP sensor or any TAC system DTCs set, diagnose those DTCs first.
4. This step tests the input circuit wiring and the PCM. If the scan tool displays approximately 5 volts, the PCM and input circuit are OK.