ABS Light weirdness

My ABS light came on today, so I restarted the car, and about 30 seconds later it came back on... I did this for a few tims with the same results. I went to a gravel parking lot to test and see if the ABS was in fact non-functional, and it wasnt working. Then while driving, I turned the car off, and back on (at about 50mph in neutral) i slammed on the brakes right after I restarted the car, and no ABS light has come on since. Any ideas what could have happened?

Mike