Information for repair work on ABS

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2009 Audi S4, 2009 Audi A4, 2008 Audi S4, 2008 Audi RS 4, and 2008 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: The anti-lock brake system is basically maintenance-free.

Testing, removing, installing and repair work may only be performed by qualified personnel.

Failure to observe the information described in this article may result in damage to the system and could make the vehicle unsafe.

NOTE:

Before carrying out repair work on the anti-lock brake system, determine the cause of the problem using On Board Diagnostic (OBD).
When installing a new hydraulic control unit, always check the coding VAS 5051 vehicle diagnostic, testing and information system.
Always switch off the ignition before carrying out installation or repair work. On vehicles with a coded radio, find out the anti-theft code and disconnect the battery Ground (GND) strap.
Observe the relevant safety precautions and information when handling brake fluid.
If hydraulic system has to be opened, bleed the braking system after the work is finished using brake filler bleeder unit VAS 5234. In addition, a high- and low-pressure test should be carried out on the brake system.
During the final road test, make sure that at least one ABS-controlled braking operation is performed (pulsations must be felt at the brake pedal) VAS 5051 vehicle diagnostic, testing and information system.
Absolute cleanliness is required when working on the anti-lock brake system; avoid any products that contain mineral oil, such as oil, grease, etc.
Thoroughly clean all connections and the adjacent areas before loosening; do not use harsh cleaning agents such as brake cleaner, fuel, thinners or similar.
Place removed parts on a clean surface and cover them up.
Carefully cover or seal open components, if repairs are not to be carried out immediately. (Use sealing plugs from repair kit 1 H0 698 311 A).
Only use lint-free cloths.
Only remove replacement parts from packaging immediately prior to installation.
Only use genuine parts in their original packaging.
When the system is open do not work with compressed air and do not move the vehicle.
Make sure that no brake fluid enters electrical connectors.