You need a mechanic. When the warning light has turned on, a diagnostic fault code has been stored in the ABS Computer. That code will lead to the circuit or system that requires further diagnosis.
The most common cause on your car is a front wheel bearing. General Motors loves to design cars with very expensive assemblies. That saves them time and money on the assembly line but often makes repair parts for their cars very expensive. The front wheel bearings develop a little looseness, which is common and normal, but since they build the wheel speed sensors into the bearing as an assembly, that looseness allows the speed signal to drop out and make it look like that wheel has locked up. Since this happens when you are not pressing the brake pedal, the computer knows the wheel has not really locked up and that missing signal is a problem, hence the warning light.
That bearing wear often causes a problem in as little as 15,000 miles. The dealers' scrap metal bins are full of old bearing assemblies. There are other possible causes for the warning light being on, and that's why having the code read is the place to start. Be aware too that some ABS Computers can only store one code at a time and some computers will not test other things while driving when something it compares it to has a code already set in memory. That means your mechanic might read the one stored code, give you an estimate for repair, perform the repair, THEN a different problem will be detected and set in memory and you have to start all over again. That can result in a lot of frustration, the assumption the mechanic didn't fix it right the first time, the assumption the mechanic doesn't know what he's doing, or the assumption he's trying to rip you off. In reality, he is just as frustrated as you are. The chance of that happening is very small if you take the car in for service right away before any second problem has chance to occur. People run into this more often when they wait months or years to get the problem fixed. That gives a lot of time for a different problem to pop up.
Sunday, February 12th, 2012 AT 9:14 PM