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 Axle Coupling Solenoid Control Circuit Short to Ground or Open

DTC C0393 0B:  Rear Axle Coupling Solenoid Control Circuit Current Above Threshold

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

High Clutch Solenoid Control

C0393 06

C0393 06

C0393 0B

--

Low Clutch Solenoid Control

C0393 06

C0393 06

C0393 0B

--

Circuit/System Description

The rear differential clutch control module (CCM) provides a power and ground switching circuits to the solenoid. The solenoid 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

Ignition ON.

Conditions for Setting the DTC

C0393 06

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

C0393 0B

A short to voltage is detected on the high or low solenoid circuit.

Action Taken When the DTC Sets

One or more of the following actions may occur:

    • All Wheel Drive Off (AWD Disabled), DIC message
    • Service All Wheel Drive (Service AWD), DIC message

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 X1 harness connector at the rear differential clutch control module.
  2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminals listed below and ground:
  3. •  terminal 5
    •  terminal 3
         ⇒If the test lamp illuminates, test the appropriate control circuit for a short to voltage.
  4. Ignition OFF, test for infinite resistance between the control circuit terminals listed below and ground:
  5. •  terminal 5
    •  terminal 3
         ⇒If less than the specified value, test the appropriate control circuit for a short to ground.
  6. Test for less than 5 ohms between the control circuit terminal 5 and control circuit terminal 3.
  7. If greater than the specified range, test both control circuits for an open/high resistance. If the circuits test normal, replace the differential clutch drum assembly.
  8. If all circuits test normal, replace the rear differential clutch control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Differential Clutch Drum Assembly Replacement
    •  Control Module References for CCM replacement, setup, and programming