Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Electronic Function
- Control module for all wheel drive (differential electronic module)
- Stepper motor
- Control valve
- Pressure flow
- Control valve cover
The differential electronic module is mounted directly onto the housing for the coupling unit. It forms part of a unit with the stepper motor and the control valve. The differential electronic module communicates with the engine control module (ECM) and brake control module via the control area network (CAN). The differential electronic module uses the sensor signals to control the oil pressure on the multi-plate clutch by adjusting the control valve. The oil pressure on the multi-plate clutch determines the torque that can be transferred to the rear wheels.
If the car has DSTC (dynamic stability and traction control), the stability control function has priority over all wheel drive.
The Active On Demand Coupling has a temperature sensor. This measures the temperature of the hydraulic fluid and transmits it to the differential electronic module. All wheel drive is disengaged if the temperature is too high. This prevents damage to the coupling unit.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.