Pontiac Repair: ABS system 1996 Grand Prix, rotor surface, wheel bearing

Question
QUESTION: Ok. Hi there. My ABS light is on after I slammed on my brakes last night for a red light. I was only going about 40mph when I did. The pedal resisted me a little, and pumped as I was coming to a stop. I have bad rotors on my car (warped a little) so I know that some of the pumping was coming from that. The ABS system, I believe, is located inside the wheel bearing, am I correct? So what does this light indicate? Is it a bad sensor? Or is it something mechanically wrong with the car? Should I be overly concerned about this, or is the car drivable till I get money to fix it? I've fixed brakes before and I know enough to pump the brakes without an ABS system. There's obviously no snow on the ground right now. Let me know what your thoughts are.

ANSWER: Hi Katiebeth

Well if the lamp came on at a panic stop I'm inclined to think the problem is with the abs unit it's self and not one of the speed sesnors. Maybe one of the valves hung up inside the abs hydrolic unit and caused the lamp to come on or possabl;y one of the motors for the valve. A panic stop shouldn't have had any effect on the speed sensors. I would have the system scanned for codes and then go from there. untill you know why the lmap is on I can't tell you what direction to go as to what is wrong with it. Good luck :)


---------- FOLLOW-UP ----------

QUESTION: Thanks for the answer. I just drove the car, a little bit slower and taking it easy on the brakes a little. The light is off. However, on my rear right wheel there is black dust all over the rim. Is this brake dust? If so, why is it there. The car doesn't feel like it's dragging something on that side, so it doesn't feel like the pad is sticking to the rotor. I have a few more questions for you about the oil.

Answer
I'd still have the system check to see what the code was for. If you have a build up of dust on one wheel more than another I would suspect that that caliper for the brakes may be hanging up or the rotor surface is rotted out and it's wearing the brake pads down on that wheel. It's worth having it checked out.