Electronic Brake Control Module: Service and Repair

ABS Control Module

Special tools, testers and auxiliary items required

• Torque Wrench (V.A.G 1783)

Removing:

- On vehicles with a coded radio, note the code. Retrieve it if necessary.

- Disconnect battery.

- Remove the hose - 1 -, loosen the hose clamps - arrows - and then remove the air guide pipe (not installed on all engines).






On Vehicles with Diesel Engine

- Remove the fuel filter - arrows -. Do not remove the fuel lines. Move the fuel filter to the side.






- Disconnect the connector for the air suspension, remove the bolts - arrows - and remove the bracket for the fuel filter.






Continuation for All Vehicles






- Remove the bolts- arrows - on the coolant reservoir - 1 -.

- Slide the coolant reservoir - 1 - in the - direction of the arrow - off the mount.

- Move the coolant reservoir - 1 - to the side.

• Do not remove coolant hoses.

- Thoroughly clean control module, hydraulic unit and surrounding area.

- Vacuum control module, hydraulic unit and surrounding area in order to prevent dirt and moisture from entering the unit.

- Release control module connector - arrow 1 - and pull off - arrow 2 -.






- Remove the control module - 2 - from the hydraulic unit - 3 - without tilting it.

The illustration shows the removed coolant reservoir lying on its side - 1 -.






- Check the valves for damage.

- Clean the sealing surface.

• Do not use aggressive cleaning agents (use cleaning agent enclosed).

• Check sealing surface for damage (visual check).

No moisture or particles of dirt must penetrate in interior of control module.

If sealing surface or contact tags are damaged, hydraulic unit must be replaced.

Excessive shaking (e.g. dropping, impact) may destroy the control module. Control module must then no longer be used.

Installing

• Use new bolts.

• A new control module may be assembled on an already used hydraulic unit twice at maximum in order to guarantee the seal of the elastic gaskets.

• Do not install a used control module.

- Carefully push the control module onto the hydraulic unit, without tilting it.

- Install the hydraulic unit and control module with the new inner Torx(R) bolts diagonally according to the tightening specification.

- Connect the connector.

- Install the coolant reservoir.

- Install the fuel filter and intake hose, if equipped.

- Enter radio code.

- Perform ABS control module (J104) coding using Vehicle diagnosis, testing and information system (VAS 5051) in "Guided Fault Finding".

- Perform a basic setting after replacing the ABS control module.