Circuit/System Verification
WARNING: This page is about a different car, the 2011 GMC Yukon, 2011 Chevrolet Tahoe, and 2011 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description .
- Ignition ON, verify the scan tool hood position parameter displays Open.
- If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
- Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0641 or P0651 are not set.
- If a DTC is set, refer to DTC P0641 or P0651 (ECM) for further diagnosis.
- Ignition ON, observe the scan tool APP Sensor 1 and 2 voltage parameters. Both readings should be between 0.30-1.2 V, and change with accelerator pedal input.
- Observe the scan tool APP Sensor 1 and 2 Agree/Disagree parameter while performing the following tests:
- Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times.
- Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.
The APP Sensor 1 and 2 Agree/Disagree parameter should display Agree.
- Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records.
- Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2120 or P2125 are the only DTCs set.
- If DTC P2120 or P2125 are the only DTCs set, replace the ECM.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.