The ABS light indicates that the computer has detected a fault and disabled the ABS system. This does not affect the normal hydraulic brake system unless the fault is in the hydraulic system itself. A large pot hole or acceleration on slick surface, anything that can allow one wheel to spin faster than the others, can cause the light to set without an actual fault being present. Resetting the light in these cases can save the average motorist around $100 in repair costs.
Carefully clean any debris or oil buildup from the master cylinder cap, and remove the cap. Top off the master cylinder level with clean brake fluid. Gently tap the side of the master cylinder reservoir with a wrench to dislodge the float for the level sensor if it is stuck.2
Remove the negative battery cable using an 8-millimeter wrench. Leave the battery disconnected for approximately 10 minutes to reset the ABS computer memory. Reconnect the negative battery cable.3
Test drive the car for a few minutes to verify the light stays off. During the test drive, the ABS computer will run a self test to check for faults in the system. If the ABS light comes back on, repairs to the system are required before the light will stay off after a reset.