I have the same problem with my '98 Buick Century. Its due to a bad ABS sensor wiring harness, in my case that is. A few other things can cause the light to come on. If its because of the wiring being bad like in my situation, you simply need to replace the wiring harness and possible the sensor itself depending upon where the damage is in the electrical circuit . The sensor's wiring goes bad usually because over time, water, dirt and road grime get into the wiring and other components of the sensor and cause damage or a electrical short somewhere. Corrosion is most likely what damaged my sensor's wiring, as I am from the Northern U.S. where salt is spread on the roads in the winter to deal with icy conditions.
These ABS sensor wiring harnesses seem to be prone to water infiltration. I first noticed the light come on during a heavy rain storm when I drove through a flooded roadway where the sewer drains clooged up. Since then, every time I would drive through a relatively deep puddle, the light would come on until I killed the engine and restarted the car.
This periodic tendancy for the light to come and go like this is most likely due to a temporary short in an electrical circuit somewhere in the sensor's wiring. The code is thrown and stays active until the car, and ECM, is restarted. But over time, the water that is getting into the wiring harness or the sensor's wiring itself is causing any ferrous metal (like in the wiring) to rust (corrode). The salt on the roads in the winter where I live only hastens the corrosion. Now, its to the point where the sensor or its wiring is so badly damaged that it permenantly throws a code. I need to replace the sensor and/or the sensor's wiring harness to keep the code from coming on.
Keep in mind that while the light is on, your anti-lock braking system will not engage when you need it to. For your information, if you start sliding and your ABS isn't working (your ABS light is on) you should pump your brakes the way you would in a car without ABS brakes. It goes without saying that you do not pump your brakes when your ABS is working properly.
I'm not sure if your situation is the same as mine. Keep in mind that you have 2 ABS sensors. Their wired from your front wheel bearings (hubs) to their respective wiring harnesses which are stationed to both front lower control arms via a metal clip on the back of the harness. I know which one is bad in my car because I found it disconnected from the control arm at one point and also because it is the side that gets wet when the code was thrown temporarily in the past. You may not have the same insight to your situation as I do in mine. Also, other things can cause this light to come on. Trapped air inside the ABS modulator assembly is one example. If you replaced the master cylinder, a brake line or valve ahead of the ABS modulator, or if you had to replace the modulator or high pressure accumulator, air can get inside the ABS modulator assembly.
Air can be very difficult to remove from an ABS modulator assembly because of all the nooks and crannies inside the unit. The modulator may have eight to 10, or more, ABS/traction control solenoid valves, plus various check valves and dead-end ports. Some ABS modulators have special bleed screws to help you vent the trapped air when bleeding the system. Others do not and require the use of a scan tool to cycle the ABS solenoids while you bleed the system.
Some low end shop mechanics more than likely will not know how to diagnose and repair this problem and tell you to take it to the dealer and pay the dealer prices. Its expensive, but its what I suggest you do if you've had any major brake work done lately and now your light won't go away. If a shop can be blamed for the trapped air, I suggest you go about getting them to pay to have it fixed, either by simply asking or by legal action.
A few other things can cause the ABS light to come on in your vehicle. The best way to pinpoint the problem is with the use of scan tool. I suggest either taking your car to a Buick dealership or to a mechanic who you know for sure is knowledgable with the specifics for your car. It wouldn't be a shock to me, however, if it ends up just being a bad sensor or a rusted wire somewhere. This seems to be the most common cause for the ABS light to come on. If the sensor itself is bad, which is common, then you have to replace the entire wheel bearing or hub assembly as it is properly referred to. They are kind of expensive (last I checked, it was like $140 per wheel bearing). The actual ABS sensors are part of the hub assembly and cannot be replaced seperately. Hope I was able to help.
Sep 13, 2008 |
1998 Buick Park Avenue