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 P0A92: Starter/Generator Performance

Circuit/System Description

The starter/generator control module (SGCM) monitors the drive belt connection between the engine and the motor generator unit (MGU). If belt slip is detected, the DTC will set.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The mechanical drive belt connection (belt slip) is detected.

Action Taken When the DTC Sets

The hybrid system is degraded.

Conditions for Clearing the DTC

    • The diagnostic system has not been disabled.
    • There are no crank sensor faults.
    • There are no engine coolant temperature sensor faults.
    • There are no mass air flow sensor faults.
    • There are no intake air temperature sensor faults.
    • There are no starter/generator temperature faults.
    • There are no starter/generator position sensor faults.
    • There are no starter/generator speed faults.
    • There are no starter/generator torque delivered faults.

Diagnostic Aids

Possible belt tension or tensioner problem.

Reference Information

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Hybrid Controls Connector End Views

Electrical Information Reference

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

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.

  1. Inspect drive belt is not damaged.
  2. If damage is found, refer to Symptoms - Engine Mechanical .
  3. Perform the Drive Belt Tensioner Diagnosis .
  4. If the engine drive belt and tensioner are within specifications, replace the MGU.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Generator with Starter Replacement .