Yup. Brake fluid and fuses aren't the cause. If a fuse was blown the yellow warning light would be on and the system would stop working.
GM has had a huge problem with front wheel bearings. They develop a little play, which is entirely normal and common but the design of the speed sensors is such that they just barely provide enough of a signal for the computer to read. The slop in the bearing causes that signal to drop out enough that the computer doesn't read it and thinks that wheel is skidding. That play in the bearings can occur in as little as 15,000 miles. The dealer's scrap metal bin is full of old bearing assemblies.
As far as the computer knows, it is reacting to a normal condition, meaning skidding, so there is no defect and no diagnostic fault code will be set. To find if only one bearing is causing the problem you have to do a test drive with a scanner connected that can display live data, then you watch which wheel speed goes to "0 mph" too soon.
Be aware too, for the benefit of others researching this problem, that there is always a long list of conditions that must be met to set a diagnostic fault code and some of those conditions are that certain other codes can't already be in memory. For example, the ABS Computer compares all of the individual wheel speeds to each other. If there is a code set for the right front, for example, it has nothing reliable to compare to the left front sensor so no code will be set for the left one if the signal disappears, (Note that loss of signal from a weak magnetic pulse is totally different than loss of that signal from a break in one of the wires which WILL still be detected). Not detecting a second problem is a big source of frustration for mechanics and customers. This can happen on other brands of cars too but it's more common on GM front-wheel-drive cars right now because of the very common wheel bearing issue. If you get the first problem fixed right away, it's usually fine until the next problem occurs. It's when you ignore the first problem for many weeks or months, then there's time for a second problem to occur, but it is likely to not set a second code so no one will know about it. Your mechanic will read the codes, diagnose the wheel bearing needs to be replaced, and give you an estimate for the repair cost. It isn't until those repairs are completed and he goes on a test drive that the next code shows up and the warning light is on again, or in your case the system is false-activating yet. Now he has to re-diagnose his work, then tell you more parts and labor are needed. You blame him for not diagnosing it right the first time, but he had no way of knowing that a second problem existed.
Monday, October 29th, 2012 AT 10:26 PM