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 Descriptors

DTC P0A06: Starter/Generator Control Module Coolant Pump Control Circuit High Voltage

DTC P0A07: Starter/Generator Control Module Coolant Pump Control Circuit Low Voltage

Circuit/System Description

The starter/generator control module (SGCM) monitors the SGCM coolant pump control circuit for an open wire or a over current condition.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

P0A06

Eco-back signal (High) does not match to the LSD output signal for 320 ms.

P0A07

Eco-back signal (Low) does not match to the LSD output signal for 320 ms.

Action Taken When the DTC Sets

P0A06, P0A07

Set engine coolant pump validity to invalid.

Conditions for Clearing the DTC

P0A06

    • LSD over current fault removed.
    • Clears 30 seconds after cycle wakeup signal.

P0A07

    • LSD wire open fault removed.
    • Normal range for 3.5 seconds.

Diagnostic Aids

P0A06

Possible over current or wire short to power line fault.

P0A07

Possible wire open or short to ground fault.

Reference Information

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Hybrid Cooling 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, be careful when working in the vicinity of the generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.

  1. Ignition ON, command the SGCM coolant pump ON and OFF with a scan tool.
  2. Observe the operation of SGCM coolant pump.

Circuit/System Testing

P0A06

  1. Verify the DTC is set as current.
  2. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal B and ground.
  4. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the SGCM.

P0A07

  1. Verify the DTC is set as current.
  2. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and control circuit terminal B.
  4. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the SGCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Generator Control Module Coolant Pump Replacement
    •  Control Module References for SGCM replacement, setup, and programming