The ABS warning light—anti-lock/anti-skid brake warning system—will come on when there is some type of fault condition with either the ABS brake system or the normal service brake system. It can also come on if the brake fluid level is low in either the master cylinder reservoir and/or the ABS brake system reservoir (if equipped).
The Bulb Check: ABS Warning Light
If only the ABS light comes on, that usually indicates there is a fault condition somewhere in the ABS brake system that the ABS computer is detecting. It is usually an electrical fault, such as a defective wheel speed sensor, defective power relay for the ABS module or pump, or, in some cases, a lower than normal fluid level in a dedicated ABS fluid reservoir.
What to Do: ABS Warning Light
If there are no other brake system warning lights on, the vehicle will have a non-operational ABS brake system, but there should be normal operation from the service brake system. The vehicle should be safe to drive to a shop as long as the vehicle owner/operator keeps in mind that in the case of an accident, there will be no ABS brake system operation. With no ABS system, the vehicle can skid out of control in a panic stop, especially on wet or slick pavement.
If there are other brake system lights on with the ABS light, then there could be something wrong with the basic service brake system. It could be something serious, such as a hydraulic problem or a serious brake fluid and/or pressure loss. In this case, it is very likely that the vehicle is not safe to drive to a shop. The safest thing to do would be to have the vehicle towed to a shop. If there is a basic service brake system problem, then there is the real possibility that the vehicle could experience a brake failure that could endanger lives.