Ok its been a whopping week and a half since my car has given me trouble....BUT I spoke too soon. Two days ago I noticed that when I'd started my car up that my Anti-Lock Brake light was on. It stayed on until yesterday when I disconnected the battery for 24 hrs. I reconnected my battery this morning, started my car. The ABS light was off. I drove it to the post office @ 30-45mph (only three blocks away) and I wanted to test my ABS so I slammed on the brakes it worked but as soon as I let off the brakes the ABS light came back on. Now it just stays on constantly and my ABS doesn't work at all. Everytime I slam on my brakes now my car slides, instead of stopping safely it feels like I'm on ice when I brake hard. I replaced the brake fluid today, and cleaned my drums, shoes, pads, and rotors with brake cleaner. I still don't know what to do, I've checked all the fuses in the car, checked for leaks, pulled all four wheels. Sometimes it works sometimes it doesn't. :( This is my THIRD Pontiac vehicle, I really love this car but its begining to become a big pain in the ***, and in my wallet as well. I've poured over $1,000.00 into the engine in the past month (with myself doing the repairs mind you, no labor charges tacked on) and all I'm getting are negative responses from this vehicle.

1997 Pontiac Bonneville SE
251,000 miles

Don't give up. I really can't say that jamming the brakes on dry surface is a valid test of ABS. You need to be on slippery conditions to really check them out. I'm not saying there isn't a problem though with your ABS. I would say have it scanned, it may be something simple.

Well, I'm not sure what the problem is, but my '97 does it as well. Make sure the electrical connectors on your wheel speed sensors are nice and clean, and put some dielectric grease on them (keeps them dry and in good contact). Like I said, mine does it every now and then, too, and I've never gotten my problem figured out. ABS tends to be a 'dealer only' kind of thing because of its complexity, so that might be one of your only options aside from checking all your wires and connections.

I hope its something simple. I wonder how much the dealership would cost to scan my ABS system. After I finished my inspection on my brake lines, flushed my brake fluid, and decided to get new front tires while they were off too I don't have any money left to have the system scanned. LOL I prommised Bessy (my Bonneville) that one day I'd have her in mint condition again. It'* a work-in-progress but I love my car and hopefully I'll find out whats the matter with it again. I disconnected the battery to reset the ECM again like I previously did (this time making sure that I don't trip the ABS light again I won't mash on the brakes unless I have to). Is there a relearing prosses that the brake system has to go through. I know my car has an ECM, PCM, ICM, and BCM all four have pre-settings I was thinking that the ABS modul had to probably give itself time to relearn how to adapt to my driving. I have no idea but oh well. :P

Usually a scan at a dealer is a flat fee of $100, or so it was when i called once. I wouldn't slam the brakes on a dry surface if you don't have to, i did that once in a caravan and it blew a valve right out the side of the ABS unit.

Ok, I think I might have found the problem with my ABS. Yesterday Venes and I were returning from the cemetary when we got about two blocks away the ABS control module under the dashboard next to the parking brake started to buzz. It happened just as he was applying the brakes to make a stop, we were going less then 25mph and the ABS kicked in. I kinda barked at him thinking that he'd slammed on the brakes on purpose. But he didn't the car didn't stop or hault. It just came to a normal coasting stop, but as it was doing that the ABS was engaging. I think my ABS control module has a short in it. The ABS light turned off after that.

Hi. A bad WSS will cause the brakes to apply by themselves. Best to take the car to a dealer and have the brake system scanned. In the meantime, you can pull the ABS pump relay. That 'self-apply' braking nonsense gets a little scary on snow-covered roads. Believe me, I've been there.

Absolutely incorrect. The ABS and TC are fail-safe by design. They CANNOT fail in any manner that will upset normal operation of the brakes. If any system fault is detected, it defaults the ABS to off.

A bad WSS will be immediately detected by loss of signal in the EBCM and the system will be inop.

I suspect something else is the culprit in the 'self apply' instance, such as slushy snow 'grabbing' the wheels or ice in the hub area. There are alot of explanations. Yes, drive the car with caution, but we need a more in-depth evaluation of the symptoms in order to diagnose properly.

The advice of getting the ABS/TC system scanned by the dealer is sound in regards to the fact that this is the only way to extract codes.

Hi Willwren. I guess I should have said a bad wss "MAY" cause self-braking to occur.
Sorry for the confusion.
These were the codes pulled from my car by the dealership:
0021-rfwss open/shorted
0022-rfwss signal erratic
0061-pump motor circuit test
0075-pcm requests tcs be disabled
They replaced the rfwss and the problem was corrected.

A WSS CANNOT cause self-braking.