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 P1A62: Starter/Generator Control Module Torque Delivered Performance

Circuit/System Description

The starter/generator control module (SGCM) monitors the internal torque value and compares it to the motor generator unit (MGU) delivered torque value. If the delivered torque is not within tolerance, the DTC will set.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

Torque error is greater than 10 N·m for 1 second.

Action Taken When the DTC Sets

Delivered torque (CAN data) = command torque.

Conditions for Clearing the DTC

Normal range for 1 second

Reference Information

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Starter/Generator Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Disconnect harness connector X2 from the SGCM. Refer to Generator Control Module Replacement.
  2. Test for 5-100 ohms between terminals 9 and 12.
  3. If within the specified range, replace the SGCM.
  4. Disconnect the X1 connector at the MGU. Refer to Generator with Starter Replacement
  5. Test for less than 1 ohm between SGCM connector harness terminal 12 and the MGU connector harness terminal A.
  6. If greater than the specified range, test the circuit for open/high resistance.
  7. Test for less than 1 ohm between SGCM connector harness terminal 9 and the MGU X1 connector harness terminal C.
  8. If greater than the specified range, test the circuit for open/high resistance.
  9. If both circuits test normal, replace the MGU.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Generator with Starter Replacement
    •  Control Module References for SGCM replacement, setup, and programming