Antilock Brakes / Traction Control Systems: Service Precautions

Notes for repair work on ABS
Before carrying out repair work on the anti-lock braking system, determine the cause of the malfunction using "guided fault finding".

"Guided fault finding" is carried out on the vehicle diagnosis, testing and information system VAS5051
^ Before working on the ABS system, disconnect the battery ground (GND) strap. On vehicles with coded radio, obtain coding.
^ Before carrying out welding work with an electric welding unit, disconnect the ABS control module.
^ When working with brake fluid, observe the relevant safety precautions and notes, go to Brake Bleeding.
^ After work for which the brake system had to be opened, bleed the brake system with brake filler and bleeder unit VAS 5234 go to Brake Bleeding.
^ During the final road test, ensure that a controlled brake test is performed at least once (pulsation must be felt at the brake pedal).
^ Absolute cleanliness is required when working on the anti-locking brake system, it is not permitted to use any products which contain mineral oil, such as oils, greases etc.
^ Thoroughly clean all unions and the adjacent areas before loosening, do not use aggressive cleaning agents such as brake cleaner, gasoline, thinners or similar.
^ Place removed parts on a clean surface and cover.
^ Carefully cover or seal open components if repairs cannot be carried out immediately. (Use sealing plugs repair kit 1 HO 698 311 A).
^ Do not use fluffy cloths.
^ Remove replacement parts from packaging immediately prior to installation.
^ Use only genuine packed parts.
^ When the system is open do not work with compressed air and do not move the vehicle. Make sure that no brake fluid enters plug connectors.
^ During painting operations, the electronic control module can be exposed to a maximum temperature of 95°C for only a short period, and to a maximum of 85°C for longer periods (approximately 2 hours).