GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Malibu 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P1A7C or P1A7D

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 P1A7C: Starter/Generator Control Module Temperature Sensor Circuit Low Voltage

DTC P1A7D: Starter/Generator Control Module Temperature Sensor Circuit High Voltage

Circuit/System Description

The starter/generator control module (SGCM) monitors the temperature sensor circuit to detect shorted low or high failure.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

P1A7C

The internal temperature sensor output voltage less than 0.2 volt for 1 second.

P1A7D

The internal temperature sensor output voltage greater than 4.6 volts for 1 second.

Action Taken When the DTC Sets

P1A7C, P1A7D

    • 50 percent maximum torque limit.
    • APM 50 percent maximum current output.

Conditions for Clearing the DTC

P1A7C, P1A7D

Return to normal range for 10 seconds.

Diagnostic Aids

P1A7C

Possible internal sensor short to ground or open.

P1A7D

Possible internal short to voltage or open.

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 Verification
  1. Verify the SGCM coolant pump operates.
  2. Ignition ON, command the scan tool SGCM coolant pump output control ON and OFF.
    3. ⇒If the SGCM coolant pump does not operate refer to SGCM Coolant Pump Malfunction.
  3. With a scan tool, clear the DTC.
  4. Ignition OFF, wait 30 seconds.
  5. Ignition ON, operate the vehicle within the Conditions for Running the DTC.
    6. ⇒If the DTC resets, replace the SGCM.

Circuit/System Testing

SGCM Coolant Pump Malfunction

  1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
  2. Ignition ON, test for B+ between the B+ circuit terminal A and ground.
    3. ⇒If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
  4. Ignition ON, command the SGCM Coolant Pump Relay ON and OFF with a scan tool. The test lamp should turn On and OFF when commanded.
    5. ⇒If the test lamp does not turn ON and OFF when commanded, test the control circuit for an open/high resistance. If the circuit tests normal, replace the SGCM
  5. If all circuits test normal, test or replace the SGCM coolant pump

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