ABS Idiot Light

Well just had service done on the car for 50,000 miles. Brakes and some other things. $1100 or so later and one month the ABS light is on. Since I have owned this 1999 this has happened a few times. I tryed to reset the codes by pulling battery but light came right on on first start-up. Any suggestions before dropping it back to the dealer. :banghead:

Probably a sensor has either gone bad or the exciter ring is chipped.