GM Service Manual Online
For 1990-2009 cars only

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 P0642: 5 Volt Reference 1 Circuit Low Voltage

DTC P0643: 5 Volt Reference 1 Circuit High Voltage

DTC P0652: 5 Volt Reference 2 Circuit Low Voltage

DTC P0653: 5 Volt Reference 2 Circuit High Voltage

Circuit/System Description

The drive motor generator power inverter module (PIM) contains two motor control modules (MCM) and a hybrid powertrain control module (HPCM). Each MCM utilizes a 5 Volt reference power supply for internal circuit needs. This fault is handled inside the PIM and no external circuits are involved.

Conditions for Running the DTC

    • The control module runs the program to detect an internal fault when the key is ON.
    • Ignition voltage is 8-18 volts.

Conditions for Setting the DTC

The control module has detected an internal malfunction.

Action Taken When the DTC Sets

    • DTCs P0642, P0643, P0652 and P0653 are Type A DTCs.
    • The PIM commands the battery energy control module (BECM) to open the high voltage contactor relays.

Conditions for Clearing the DTC

DTCs P0642, P0643, P0652 and P0653 are Type A DTCs.

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification

  1. Clear the DTC information.
  2. Turn the ignition OFF for 1 minute.
  3. Turn the ignition ON.
  4. Retest for DTCs P0642, P0643, P0652 and P0653.

Circuit/System Testing

  1. Clear the DTC and operate the vehicle under the condition for running and setting the DTC.
  2. Shut the ignition OFF for 30 seconds, and verify that the DTC does not reset.
  3. If the DTC resets, replace the Drive Motor Generator Power Inverter Module Assembly (PIM).

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PIM replacement, setup, and programming.