Procedures

Notes for repair work on Anti-lock Brake System
^ Before performing repairs to the ABS, determine the cause of the malfunction via "Guided Fault Finding".
"Guided fault finding" is performed with On Board Diagnosis, using vehicle diagnosis, testing and information system VAS 5051.
^ Disconnect Ground (GND) cable from battery with ignition off.
^ Before carrying out welding work with an electric welding unit disconnect ABS control module.
^ When working with brake fluid, observe relevant safety precautions and notes Brake system, bleeding.
^ After finishing any work that required opening the brake system, bleed the brake system using Brake Charger/Bleeder Unit VAS 5234 Brake system, bleeding.
^ During final road test, carry out at least one ABS-controlled braking operation (appropriate pulsations must be felt at brake pedal).
^ Absolute cleanliness is required when working on the anti-lock brake system, it is not permitted to use any products which contain mineral oil, such as oils, greases etc.
^ Thoroughly clean all unions and adjacent areas before loosening. Do not use aggressive cleaning agents such as brake cleaner, fuel, thinners or similar chemicals.
^ Place parts that have been removed on a clean surface and cover.
^ After disconnecting control module/hydraulic unit, use transport protection for valve body.
^ Carefully cover over opened components or seal, if repairs are not carried out immediately. (Sealing plugs, use repair kit 1 H0 698 311 A)
^ Only use lint-free cloths.
^ Only unpack replacement parts immediately prior to installation.
^ Only use genuine parts.
^ Do not work with compressed air and do not move vehicle while system is open.
^ When painting, electronic control module can be exposed to a maximum temperature of 95° C only briefly, and to a maximum of 85° C for longer periods (approximately 2 hours). Make sure that brake fluid does not enter harness connectors.