P2123
CIRCUIT DESCRIPTIONThe accelerator pedal position (APP) sensor is made up of 2 sensors that are housed inside one assembly. The engine control module (ECM) supplies a separate 5-volt reference and low reference circuit for each of the sensors. The 5-volt reference for APP sensor 1 is supplied from the same source in the ECM as the 5-volt reference for the mass air flow (MAF) sensor and the fuel tank pressure (FTP) sensor. The 5-volt reference voltage for all of the sensors is supplied on separate ECM terminals, but the terminals are connected internally to a voltage supply. The APP sensor 1 sends a signal from the sensor to the ECM indicating the accelerator pedal position. The ECM actuates the throttle plates based on this information. The APP sensor 1 signal voltage increases as the pedal is depressed, from approximately 0.8 volts at rest to above 3.5 volts when fully depressed. If the ECM detects that the signal voltage is excessively high, DTC P2123 sets.
CONDITIONS FOR RUNNING THE DTC
- The ignition is ON.
- The battery voltage is more than 10 volts.
- The accelerator pedal is not in the rest position.
CONDITIONS FOR SETTING THE DTC
The APP sensor 1 voltage is more than 4.8 volts for more than 140 milliseconds.
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 3 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.
TEST
Steps 1-3:
Steps 4-6:
Steps 7-10:
Steps 11-15:
