ABS Repair Information

ABS Repair Information

Special tools, testers and auxiliary items required

• Vehicle diagnosis, testing and information system (VAS 5051)

• Brake charger/bleeder unit (VAS 5234)

• Before carrying out repair work on the Anti-lock Brake System (ABS), as well as the control module coding, determine the cause of the malfunction using "guided fault finding".

"Guided fault finding" is performed with On Board Diagnosis (OBD), using the (VAS 5051).

• Disconnect the negative battery cable from with the ignition off.

• Carry out before welding with an electric welding tool.

• When working with brake fluid, observe relevant safety precautions and notes. Refer to --> [ Brake System, Bleeding ] Brake System, Bleeding.

• After work for which the brake system had to be opened, bleed the brake system using the (VAS 5234) or the (VAG 1869). Refer to --> [ Brake System, Bleeding ] Brake System, Bleeding.

• During the 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 ABS. Do not 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, fuel, thinners or similar chemicals.

• Place parts that have been removed on a clean surface and cover.

• After disconnecting the control module/hydraulic unit, use the transport protection for the valve domes.

• Carefully cover over opened components or seal, if repairs are not carried out immediately. (Use plugs (1H0 698 311 A))

• Only use lint free cloths.

• Only unpack replacement parts immediately prior to installation.

• Only use parts in their original packaging.

• Do not work with compressed air and do not move vehicle while the system is open.

• When painting, the 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.