For 1990-2009 cars

### 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 C0393 0B: Rear Axle Coupling Solenoid Valve Control Circuit High Current

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Control | C0393 0B | 1 | 1 | C0393 0B
1. Differential Lock Malfunction

### Circuit/System Description

The rear axle coupling solenoid valve is installed at the rear halfshaft leading to the rear left wheel. The rear differential clutch control module supplies battery voltage to the control circuit and ground to the low reference circuit of the solenoid valve. The solenoid valve is controlled by a pulse width modulation (PWM) signal. The solenoid valve controls the hydraulic pressure to the clutch package of the limited slip differential. The locking level of the limited slip differential depends on the engagement of the clutch package.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The rear differential clutch control module detects a short to ground on the high solenoid valve control circuit.

or

The rear differential clutch control module detects a current more than 5.7 A.

### Action Taken When the DTC Sets

One or more of the following actions may occur:

• | All-wheel drive (AWD) is disabled.

• | Service AWD is displayed on the driver information center.

### Conditions for Clearing the DTC

• | The condition for the DTC is no longer present.

• | The DTC is not detected in 40 consecutive power cycles.

### Reference Information

#### Schematic Reference

Rear Axle 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 Verification

Engine running, observe the scan tool Rear Differential Clutch Status parameter. The reading should be NORMAL when stationary.

### Circuit/System Testing

1. Ignition OFF, inspect for damage of the wire, the solenoid or the housing.

⇒ | If a damage is visible, replace the appropriate component.

2. Disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
3. Test for a infinite resistance between the control circuit terminal and ground.

⇒ | If not within the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the Q49 Rear Axle Coupling Solenoid Valve.

4. If the circuit tests normal, replace the K47 Rear Differential Clutch Control Module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Limited Slip Differential Clutch Valve Replacement

• | Control Module References for rear differential clutch control module replacement, setup, and programming