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Service message Rear axle lights constantly

Service message Rear axle lights constantly

Diagnosis instructions


• Perform Diagnostic System Check - Vehicle before performing this diagnostic procedure.

• See Strategy based diagnosis for an overview of the diagnostic procedure.

• Instructions for diagnosis procedure provides an overview of each diagnostic category.


Diagnosis, fault information

Circuit Short circuit to ground Open circuit/High Resistance Short circuit to voltage Signal Performance
Ground - 1 - -
B+ 1 1 - -
Ignition 1 1 - -
1. Service message Rear axle lights constantly


Circuit/System description

The rear differential clutch control module is connected to the chassis expansion bus. The serial data message is used to control the use/driving situations for the vehicle and to determine how much driving torque should be transferred to the rear wheels. Using data on the serial data buses, the rear differential control module calculates the distribution of torque between both front and rear axles, and between the right and left wheels (for vehicles equipped with differential clutch for limited slipping, LSD).

Reference Information


Schematic Reference

• Rear Axle Schematics

• Data Communication Schematics


Component connector end view reference

Component Connector End Views

Description and Operation

Rear Drive Axle 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 information about the scan tool.

Circuit/System verification


1. Check that no DTCs have been set.

2. If one or more DTC have been set.

Diagnose these DTCs first. Go to Diagnostic Trouble Code (DTC) list - vehicle

3. If no DTCs have been set.

4. Try to communicate with K47 rear differential clutch control module.

5. If K47 rear differential clutch control module does not communicate

Continue to Circuit/System test.

6. If K47 rear differential clutch control module communicates

7. Refer to the following:

• Test for electrical intermittent state

• Induce an intermittent fault state

8. Everything is OK


Circuit/System testing


1. Ignition OFF and all vehicle systems OFF. Disconnect the wiring harness connectors from K47 rear differential clutch control module. It can take up to 2 minutes for all vehicle systems to be shut down.

2. Check that it is less than 10 Ω between the ground circuit connection L, X1 and ground.

3. If 10 Ω or more

Repair the open/high resistance in the circuit.

4. If less than 10 Ω

5. Ignition ON.

6. Check that a test light comes on between the B+ circuit connection M, X1 and ground.

7. If the test light does not come on and the circuit fuse is intact

7.1. Ignition OFF.

7.2. Check that there is less than 2 Ω on the B+ circuit end to end.

7.3. If 2 Ω or more, repair the open/high resistance in the circuit.

7.4. If less than 2 Ω, check that the fuse is intact and that there is voltage on the fuse.

8. If the test light does not come on and the circuit fuse is intact

8.1. Ignition OFF.

8.2. Check that there is infinite resistance between the B+ circuit and ground.

8.3. If less than infinite resistance, repair the short circuit to ground in the circuit.

8.4. If infinite resistance, replace K47 rear differential clutch control module.

9. If the test light is lit

10. Ignition ON.

11. Check that a test light comes on between the ignition circuit connection F, X1 and ground.

12. If the test light does not light

12.1. Ignition OFF.

12.2. Check that there is less than 2 Ω on the ignition circuit end to end.

12.3. If 2 Ω or more, repair the open/high resistance in the circuit.

13. If the test light is lit

14. Replace K47 rear differential clutch control module.


Repair instructions

Perform Confirmation of diagnostic repair after completing the repair.

Control Module References for changing the rear differential clutch control module, programming and start up