P2128

DTC P2128

CIRCUIT DESCRIPTION




The accelerator pedal position (APP) sensors 1 and 2 are located within the accelerator pedal assembly. Each sensor has the following circuits:
- A 5-volt reference circuit
- A low reference circuit
- A signal circuit

The APP sensor provides the engine control module (ECM) with a signal voltage proportional to accelerator pedal movement. The APP sensor 1 signal voltage at rest position is near the low reference and increases as the pedal is actuated. The APP sensor 2 signal voltage at rest position is near the 5-volt reference and decreases as the pedal is actuated.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage

CONDITIONS FOR RUNNING THE DTC
- The battery voltage is more than 5.25 volts.
- The ignition is ON.
- DTC P2128 runs continuously when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for more than 0.5 second.

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 and/or the Failure Records.
- The control module commands the TAC system to operate in the Reduced Engine Power mode.
- A message center or an indicator displays Reduced Engine Power.
- Under certain conditions the control module commands the engine OFF.

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.

DIAGNOSTIC AIDS
The ECM compares the signal of each of the APP sensor to each other throughout the entire range of operation. Clear the DTCs and actuate the pedal through the entire range with the ignition ON and the engine OFF.

Use the J 35616-B Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.

For intermittent conditions,

TEST DESCRIPTION

Steps 1-10:

The number below refers to the step number on the diagnostic table.
2. Any circuit faults on either APP sensor 1 or APP sensor 2 will set one of the DTCs listed. Refer to the appropriate table for diagnosis.