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 C0393 06:  Rear Differential Clutch Control Coil Circuit

DTC C0393 0B:  Rear Differential Clutch Control Coil Circuit Current Above Threshold

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

AWD Supply Voltage

C0393 06

C0393 06

C0393 0B

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Low Reference

C0393 06

C0393 06

C0393 0B

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Circuit/System Description

The rear differential clutch control module (CCM) provides a power and ground switching circuits to the coil. The coil receives current from the CCM through PWM low side driver, and converts that signal into torque through the clutch to the rear tires when all wheel drive (AWD) is requested.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

    • An open is detected on the high or low coil circuits.
    • A short to ground is detected on the high or low coil circuit.

Action Taken When the DTC Sets

One or more of the following actions may occur:

    • All Wheel Drive Off (AWD Disabled).
    • Service All Wheel Drive (Service AWD).

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • The DTC is not detected in 40 consecutive drive cycles.

Reference Information

Schematic Reference

All-Wheel Drive Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

All-Wheel Drive 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. Ignition OFF, disconnect the X2 harness connector at the clutch control module .
  2. Ignition ON, verify a test lamp does not illuminate between the following circuits and ground:
  3. • Low Reference terminal 3
    • Voltage terminal 5
         ⇒If the test lamp illuminates, test the appropriate circuit for a short to voltage.
  4. Ignition OFF, test for infinite resistance between the following circuit terminals and ground:
  5. • Low Reference terminal 3
    • Voltage terminal 5
         ⇒If less than the specified value, test the appropriate circuit for a short to ground.
  6. Test for less than 5.0 ohms of resistance between the low reference circuit terminal 3 and the voltage supply terminal 5.
  7. If greater than the specified range, test the appropriate circuit for an open/high resistance. If the circuits test normal, replace the rear wheel driver module clutch housing.
  8. If all circuits test normal, replace the CCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for CCM replacement, setup, and programming