Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0AC4: Hybrid Powertrain Control Module Requested MIL IlluminationCircuit/System Description
The hybrid powertrain control module (HPCM) uses the GMLAN to signal the engine control module (ECM) that the hybrid system is requesting malfunction indicator lamp (MIL) illumination. This happens when the HPCM has determined that a failure affecting the hybrid system has occurred. When the ECM receives the message from the HPCM, DTC P0AC4 will set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The HPCM is requesting MIL illumination.
Action Taken When the DTC Sets
DTC P0AC4 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P0AC4 is a Type A DTC.
Diagnostic Aids
DTC P0AC4 can not be cleared from the ECM until the related hybrid codes have been cleared.
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Refer to Diagnostic Trouble Code (DTC) List - Vehicle to correct any hybrid DTCs.
