ABS modules are electronic systems which monitor wheel speed and adjust braking power as necessary during emergency stops to prevent wheel lockup. On each wheel which has the ABS system monitoring it there is usually a toothed ring. These look like gears and are used by the wheel speed sensor to monitor each wheel's speed during braking. Some 2WD (two wheel drive) ABS systems use a vehicle speed sensor located on the transmission. Whenever one of the wheels is detected to be locking, the ABS sytem quickly relieves the pressure being applied to that wheel to attempt and maintain maximum traction. This action is performed very rapidly and causes the very noticable pulsating in a brake pedal when the system activates.
ABS Modules can fail, causing the system to cease functioning, or not function adequately. Usually a trouble code will be available to diagnose this failure.
Replacing an ABS module may be as simple as bolting a new one on, or could require complex repairs involving the brake hydraulic system.
We stock and sell a wide variety of reliable ABS modules from these manufacturers: