Control Unit: Service and Repair

Differential electronic module (DEM), replacing

Note! As the illustrations in this service information are used for different model years and / or models, some variation may occur. However, the essential information is always correct.

Preparatory work
Ignition off.
Wait 3-4 minutes after the ignition is switched off to minimize oil leakage on removal.

Removal

Removing the differential electronic module (DEM)

Note! Clean the area around the control module thoroughly before beginning removal.




Position a container underneath the Active on Demand Coupling.
Disconnect the connectors for the control module and the oil pump.

Remove:
- the 2 screws for the control module
- the control module with the sealing plate and the cupped washer.

Removing components from the Active on Demand coupling




Remove the choke valve and the temperature/pressure sensor from the coupling.
A = choke valve.
B = temperature/pressure sensor.
To remove, grasp the end of the choke valve. Use a large pliers. Hold the pliers steady. Pull the valve straight out.

Remove:
- the temperature/pressure sensor as above
- The O-ring from the choke valve seat in the Active on Demand Coupling housing.

Installation

Installing relevant components





Install:
- control module
- sealing panel
- washer
- the choke valve with O-rings
- the temperature/pressure sensor with O-ring
- the O-ring for the choke valve seat
- the screws.

Positioning the sealing panel in the control module




Press the choke valve and temperature/pressure sensor into place on the control module contacts.
Place the cupped washer with the convex side against the temperature/pressure sensor.
Lubricate the sealing rings on the valves with oil, P/N 116 1641-4 (0.3 litres).

Installing the O-ring




Carefully check that the mating surface for the control module and the valve seats in the Active on Demand Coupling are clean. There must be no lint or traces of paper or rags.
Lubricate the new O-ring with oil, P/N 116 1641-4 (0.3 litres). Press the O-ring into place in its seat.

Installing the control module for the Active on Demand Coupling




Install the control module with valves in the coupling. Hold the control module pressed against the coupling housing while the 2 screws are installed and lightly tightened alternately. Tighten. See the relevant specifications.
Connect the connectors to the control module and the oil pump.
Fill the Active on Demand Coupling with oil. Check the oil level. See Clutch (AOC), replacing, M58, M66 AWD, AW50/51 AWD Clutch (AOC), Replacing.
Erase any diagnostic trouble codes (DTCs).





Ordering software
Order software for the differential electronic module (DEM) according to the table below.