P2138
DTC P2138 - ACCELERATOR PEDAL POSITION (APP) SENSOR 1-2 CORRELATION
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 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 volt 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 volt.
- The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.27 volt 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 Engine Controls 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
Step 1 - Step 6:
Step 7 - Step 12:
