P2138
DTC P2138
CIRCUIT DESCRIPTION
The accelerator pedal assembly contains two 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 volt at rest to above 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volts at rest to more than 2 volts with the accelerator pedal fully depressed.
If the ECM detects that the difference between APP sensor 1 and 2 signal voltage is more than a predetermined value, this DTC sets.
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 7.0 volts.
- The ignition is ON or the engine is operating.
- DTC P2138 run continuously once the above conditions are met for more than 1 second.
CONDITIONS FOR SETTING THE DTC
This DTC set when one of the following conditions occur:
- The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.21 volts.
- The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.27 volts with a partially pressed pedal.
- The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 1.07 volts with a fully pressed pedal.
- The ECM detects that the APP sensor 1 voltage is more then 1.17 when leaving the idle range and the voltage difference between APP sensor 1 and 2 is more than 0.04.
- Any of the above conditions exist for less than 4 seconds.
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/Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
- 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 emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
- Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
- The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to Computers and Control Systems Component Views.
- If DTCs P0700, P2122, P2128, and P2138 are set together in various combinations, inspect the APP sensor 1 and 2 signal circuits for being shorted together.
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions
TEST
Steps 1-5:
Steps 6-10:
