why does abs light come on after driving a distance.

Hello, The ABS module constantly monitors the ABS and traction control system for faults. It takes specific conditions to trigger an ABS light, and that may mean the computer (ABS module) needs to record the issue for a predetermined mileage or time before setting the ABS warning. Most times, the ABS warning light displays as a result of a bad wheel speed sensor, but there are several other components, including the ABS module itself, that can cause the light to illuminate. Since the ABS kicks in while you touch the brakes, the vehicle likely thinks you are skidding due to a bad wheel speed sensor. Especially if only one wheel is pulsating.