If the abs light is on you need to go to autozone and have them scan the computer for trouble codes. They scan for free, mechanic shops and dealerships charge an arm and a leg. But you chan check your brake fluid before you go to make sure its not low. I have seen the pulse ring break a few teeth off and set off the abs light. The anti-lock brake system has a lot of small parts that make it work. There could be a problem with any number of them. Have the codes scanned to help narrow down the search.