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 C0403 62: Transfer Case Solenoid Valve Stuck Open

### Diagnostic Fault Information

Component | Condition | DTCs
--- | --- | ---
Pump/Oil Filter Reverse Valve | Pump motor is spinning backwards because of clogged filter. | C0403 62

### Circuit/System Description

The hydraulic pump delivers both solenoid valves with hydraulic oil pressure, the transfer solenoid valve and if installed the rear differential clutch solenoid valve. The pump is installed in the torque transfer device housing. The pressure of the system is calculated by means of the rear differential clutch control module measuring the motors power consumption. When the pressure reaches approximately 3200 kPa (464 PSI) the rear differential clutch control module recognizes that the system pressure has been reached. The pump is shut down. If a voltage is detected after the pump is shut down after a certain limit an error is detected. The pump is spinning backwards.

### Conditions for Running the DTC

• | The ignition is ON.

• | Test runs in temperature interval 0-80°C (0-176°F).

### Conditions for Setting the DTC

A test voltage is applied to the transfer case solenoid valve. An error is detected if the resultant current is greater than the current which corresponds to less than 2 Ω in the solenoid valve.

### 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 diagnostic tester 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, replace the oil filter in the torque transfer device housing.
2. Ignition ON, drive the car under normal conditions. Verify the DTC does not reset.

⇒ | If the DTC resets, replace the K47 Rear Differential Clutch Control Module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Differential Clutch Oil Filter Replacement

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