• 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.

For symptom byte information, refer to Symptom Byte List

The pressure in the hydraulic circuit is controlled by the differential clutch pump. The differential clutch pump utilizes a brushless motor and a radial piston pump. The motor in the differential clutch pump is controlled utilizing a bi-directional control that applies power and ground to each control circuit. By reversing the polarity of the motor, the differential clutch pump is able to spin both clockwise and counter-clockwise as a means to increase and decrease pressure in the system. The differential clutch pump is constantly increasing or decreasing the pressure in the system according to the torque request signal as controlled by the rear differential clutch control module.

• The engine is running.
• Battery voltage is between 9-16 V.
• The engine speed is above 400 rpm.

• The engine is running.
• The starter motor commanded on is false.
• Battery voltage is between 9-16 V.
• The engine speed is above 400 rpm.

• The engine is running.
• The engine speed is above 400 rpm.

When voltage for motor phase U, V, and W is above 1.0 V.

When voltage for motor phase U, V, and W is below 7.0 V.

When voltage for motor phase U, V, and W is below 7.0 V.

The bridge driver circuit detects shunt voltage above 0.16 V.

A rear differential clutch control module has detected a short between U, V, and W phases.

The rear differential clutch control module detects implausible voltage reading.

The rear differential clutch control module determines the differential clutch pump is stuck.

The rear differential clutch control module determines the differential clutch pump is slipping.

• Electronic limited slip is disabled for the duration of the key cycle.
• The AWD SERVICE message is displayed in the driver information center.

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

Rear Axle Schematics

Master Electrical Component List

Rear Drive Axle Description and Operation

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

1. Verify that DTC C0407 with symptom byte 01, 02 or 04 is not set.
• If the DTC is set

  Refer to Circuit/System Testing.

• If the DTC is not set
2. Verify the differential clutch oil level is correct. Refer to Rear Axle Lubricant Level Inspection.
• If the differential clutch fluid level is below specifications
1. Verify the rear axle lubricant level is correct. Refer to Rear Axle Lubricant Level Inspection.

Note: If the vehicle is unable to complete the rear differential hydraulic system service fill/bleed procedure, the M32 Differential Clutch Pump may have been damaged by the low differential clutch fluid level.

If the rear axle lubricant level is above specifications, the differential clutch may be leaking differential clutch oil into the rear axle lubricant. Inspect for and correct any internal fluid leaks between the differential clutch oil and the rear axle lubricant. Refer to Rear Differential Carrier Leak Diagnosis. After the repair has been completed, perform the Rear Differential Hydraulic System Service Fill/Bleed.
• If the rear axle lubricant level is below specifications, inspect for fluid leaks and fill as required.
• If the rear axle lubricant level is correct.
2. Verify there are no external differential clutch oil leaks.
• If any external differential clutch oil leaks are observed, repair as necessary and perform the Rear Differential Hydraulic System Service Fill/Bleed.
• If there are there are no external differential clutch oil leaks.
3. Perform the Rear Differential Hydraulic System Service Fill/Bleed procedure.
4. Verify the vehicle is able to complete the rear differential hydraulic system service fill/bleed procedure.
• If the vehicle is unable to complete the rear differential hydraulic system service fill/bleed procedure, test or replace the M32 Differential Clutch Pump.
• If the vehicle is able to complete the rear differential hydraulic system service fill/bleed procedure.
5. Clear all DTCs.
6. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
• If the DTC sets, test or replace the M32 Differential Clutch Pump.
• If the DTC does not set.
7. All OK.
• If the differential clutch fluid level is correct
3. Perform the Rear Differential Hydraulic System Service Fill/Bleed.
4. Verify the vehicle is able to complete the rear differential hydraulic system service fill/bleed procedure.
• If the vehicle is unable to complete the rear differential hydraulic system service fill/bleed procedure, perform the Rear Differential Hydraulic System Service Fill/Bleed two additional times. If the vehicle is unable to complete the rear differential hydraulic system service fill/bleed procedure after three attempts, replace the M32 Differential Clutch Pump.
• If the vehicle is able to complete the rear differential hydraulic system service fill/bleed procedure.
5. All OK.

1. Ignition OFF, disconnect the harness connector at the M32 Differential Clutch Pump, Ignition ON/Vehicle in Service Mode.
2. Test for 3.3–5.3 V AC between the control circuit terminal 8 and ground.
• If less than 3.3 V AC
1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for infinite resistance between the control circuit terminal 8 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit terminal 8 end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.
• If greater than 5.3 V AC
1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
2. Test for less than 1 V between the control circuit terminal 8 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K47 Rear Differential Clutch Control Module.
• If between 3.3–5.3 V AC
3. Test for 1.2–3.7 V between the control circuit terminal 7 and ground.
• If less than 1.2 V
1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for infinite resistance between the control circuit terminal 7 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit terminal 7 end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.
• If greater than 3.7 V
1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
2. Test for less than 1 V between the control circuit terminal 7 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K47 Rear Differential Clutch Control Module.
• If between 1.2–3.7 V
4. Test for 6.4–6.8 V between the control circuit terminal 6 and ground.
• If less than 6.4 V
1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for infinite resistance between the control circuit terminal 6 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit terminal 6 end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.
• If greater than 6.8 V
1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
2. Test for less than 1 V between the control circuit terminal 6 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K47 Rear Differential Clutch Control Module.
• If between 6.4–6.8 V
5. Ignition OFF, disconnect the scan tool and disconnect the harness connector at the M32 Differential Clutch Pump.
6. Test for greater than 25 Ω between the following control circuit terminals listed below.
• Control Circuit Terminal 6
• Control Circuit Terminal 7
• Control Circuit Terminal 8
• If 25 Ω or less
1. Disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for infinite resistance between the three control circuits.
• If less than infinite resistance, repair the short between the three circuits.
• If infinite resistance, replace the K47 Rear Differential Clutch Control Module.
• If greater than 25 Ω
7. Test or replace the M32 Differential Clutch Pump.
8. Operate the vehicle under the conditions for setting the DTC, the DTC should not set.
• If the DTC sets

  Replace the K47 Rear Differential Clutch Control Module.

• If the DTC does not set
9. All OK.

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification

• Differential Carrier Assembly Replacement for M32 Differential Clutch Pump.
• For control module replacement, programming, and setup refer to:Control Module References