ABS
This happened on my uncles truck, we took the speed sensor out, cleaned it, and everything was good. Speed sensors are really cheap (like 10-20 dollars). On his truck is was 1 bolt that held in it so it is really easy to replace. I would try to clean it off first (if that was the problem you may want to replace your diff fluid, my uncle had a big chunk of rubbery diff fluid on the speed sensor).
The ABS light has been on in the truck I bought 2 months ago. A friend brought his code reader over last weekend and it read C1095, which is pump motor circuit failure. The friend had the ABS light on his truck also. He had a bad wire going into the pump motor. All he did was remove the tape on the wires and found a bad spot. Removed this, reconnected, and the light went off. So, could be a lot of different things without actually reading the code.





