There are times when the anti-lock brake warning light may come on your car's dashboard when the brakes are in good condition. It may even happen after you have recently had the brakes serviced. If you know your car's anti-lock brake system is in good condition and the light is still on, there are some steps you can take to reset the light. The problem most likely lies in the car's central computer or ABS sensor, but it can also be from something else in the brake or electrical system.
Disconnect the positive cable from the car battery, and then hold down on the brake pedal to drain the car's electrical system. This will reset the car's central computer. Plug the positive cable back to restore the power. Even if this doesn't totally reset the light, it should stay off for up to 1 week.
Change the ABS sensor if the light comes back on. Unscrew the housing for the sensor that is mounted to the wheel hub and unplug the wire, then attach and mount a new sensor. You might need to reset the computer again as described above.
Connect an OBD code reader to your car's on-board diagnostics system to determine any other causes of the brake light. Look for codes related to the brakes that appear on the reader, indicating any parts on the brakes that need repair or replacement.
Take the car to an auto supply store or your mechanic if you don't have access to your own OBD code reader. A service technician can use such a tool to read the car's diagnostic problems.