P2123

DTC P2123

CIRCUIT DESCRIPTION
The DTC P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage diagnostic detects a high APP sensor 1 signal. 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 volts 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 P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage

CONDITIONS FOR RUNNING THE DTC
- The ignition is ON or the engine is running.
- DTC P2123 runs continuously once the above condition has been met.

CONDITIONS FOR SETTING THE DTC
The APP sensor 1 voltage is more than 4.8 volts 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 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 12:

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.
4. This step tests for a short to voltage on the APP sensor 1 signal circuit. With the sensor disconnected, the signal circuit should be near zero volts.