Did you know that the Antilock Braking System (ABS) warning light means the ABS system has been deactivated because of a self-diagnosed fault? Even though this is the case normal braking “should” still remain. The vehicle should be safe to drive under normal conditions provided the driver does not have to call on the ABS system when panic braking on a wet or slick surface. ABS is essentially an add-on to the existing brake system which only comes into play when traction conditions are marginal or during sudden panic stops. The rest of the time, it has no effect on normal driving or braking.
An ABS warning light can come on for several reasons. One reason may be a loss of power-assist if the vehicle has an ABS system relying on an electric pump and pressure accumulator pump rather than a conventional vacuum brake booster. The car will still brake, but will not have the usual power assist. This creates an unsafe situation for drivers who have difficulty braking without power assisted brakes. An ABS warning lamp that comes on when the car starts moving, or anti-lock braking operation where valve cycling occurs during normal stops on dry pavement, often (But not always) indicates a problem with one of the wheel speed sensors.
When both brake and antilock warning lights are on, and there is a lack of normal power assist, the pump may be inoperative on applications that have an integral ABS system. When both warning lamps are on and power assist is present, it may indicate low brake fluid level or loss of hydraulic pressure in one of the brake circuits. If brakes are pulling or grabbing during normal braking, it is usually not an ABS problem. This could indicate that vehicle has a conventional brake problem needing attention. A brake warning lamp (not ABS lamp) that remains on or comes on while driving, usually indicates a problem with the hydraulic system, not the ABS system. There may be a fluid leak or loss of pressure, either of which pose a danger to safe braking. The cause of the brake warning light (and ABS light) should be investigated by a certified technician immediately. When either the ABS or brake warning lights are on, the vehicle will not pass Virginia State Inspection. This is considered “defective equipment”.
Mark Martin’s Auto World services most ABS systems on passenger cars, light trucks and SUV’s whether domestic or import. We service ABS pumps and control modules providing a lifetime warranty on many models. We have the latest ABS diagnostic equipment availale. If your ABS light or your brake warning light is on, don’t hesitate to call us for diagnosis and repair. Mark Martin’s Auto World technicians are ASE certified and are prepared to handle your brake problems.