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 C0406 0B: Transfer Case Solenoid Valve Control Circuit High Current

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Control | C0406 0B | -- | -- | C0406 0B

### Circuit/System Description

The transfer case solenoid valve and the oil pump are installed in the torque transfer device housing of the rear drive module. The rear differential clutch control module supplies battery voltage to the control circuit and ground to the low reference circuit of the solenoid valve and the oil pump motor. 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 torque transfer device. The locking level depends on the engagement of the clutch package. The oil pump motor produces the oil pressure for both oil cycles.

### 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 control circuit of the solenoid valve and the oil pump motor.

or

The rear differential clutch control module detects a current more than 11 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 Drive Clutch Status parameter. The reading should be NORMAL when stationary.

### Circuit/System Testing

1. Ignition OFF, inspect for signs of damage of the K47 Rear Differential Clutch Control Module, the M32 Oil Pump Motor or the rear drive module 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. Ignition OFF, test for infinite resistance between the control circuit terminal W2 at the M32 Oil Pump Motor and ground.

⇒ | If less than the specified value, replace the M32 Oil Pump Motor.

4. Disconnect the K47 Rear Differential Clutch Control Module.
5. Test for infinite resistance between the terminal 1 at the Q48 Transfer Case Solenoid Valve and ground.

⇒ | If less than the specified value, replace the Q48 Transfer Case Solenoid Valve. If the circuits test normal, replace the K47 Rear Differential Clutch Control Module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Rear Differential Clutch Control Module Replacement

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