When fixing or replacing an ABS control unit, remember that in some cases, the module has to be reprogrammed before driving the vehicle. In some cars and trucks, the brake system must be flushed after replacing the module.
Drivers should look for certain symptoms when deciding if the ABS control module needs repair or replacement. Common symptoms include the illumination of the ABS light on the dashboard, the check engine light illuminating, abnormal braking behavior and a disabling of the traction and stability controls. ABS systems are programmed to constantly run self-checks, and if an ABS system finds a problem, it can shut itself down and notify the driver by illuminating the brake light on the dashboard.
When repairing an ABS system because of an illuminated brake light, be sure the ABS control module is truly faulty because the light may be on to indicate problems with the normal brakes. Do this by inspecting the brakes while looking for things such as air in the brake line or inadequate brake fluid levels. If the ABS control module is malfunctioning, find a manual for the make and model of the vehicle. Unplug and reinsert the ABS module before incurring the expense of buying a new module. When in doubt, seek the advice of an automotive technician.