On my brothers car, ya popped the tire off, take the caliper off and take the rotors off. If you look at the assembly that has the wheel studs attached to it (and rotates with the tires) on one of the sides will be a long fixed thing that looks kinda like a tootsie roll (alittle larger) but that general shape. If I remember correctly, it is stationary and measures through magnatism the rotation of the wheel. Check that when you can. Like I said, I just brushed it off with a rag.
1993 CV LX Silver with Silver Interior