Thread: ABS Issue

Originally Posted by m1sterb0b

Okay . . . I've had it!

I just bought my first Grand Prix. Its a 1997 Grand Prix GT Coup (3.8 non-supercharged). BEAUTIFUL car! I live in michigan, and its a kansas car, so it has little rust on the body. I've had some minor well-known issues with the car (such as a rear strutt going out/knocking, one of the cv joints just blew, and one of my window motors doesn't work well) all things I can fix. However, I have one issue that I can't figure out.

My ABS / Traction Control / Tire Pressure lights come on, and it seems random. Normally you can tell if its a sensor by when the lights come on, but they just come on whenever they feel like it. For instance: I can start my car, on a cool day, and within 1 or 2 seconds the lights will come on, while Other times, I can start my car, drive around for an hour or two and the lights will never come on. Sometimes I can be driving and the lights will come on a half an hour down the road, other times I'll be driving and my ABS will just go nuts (I actually went through a red light once because my ABS was going off so much).

I've had all 4 wheels off checking the links. All 4 connections seem solid, we unplugged them, checked for corrosion, and there was corrosion on only 1 of the connections, which we fixed, and plugged all back in making sure they were solid and connected to their clips. The front 2 wheel bearings look like they were recently replaced. The rear 2 look like they may be originals, but I don't hear any noise coming from them while driving. When we had the tires off, and we spun them, we didn't hear anything and they spun just fine.

What else can I do to figure out whats wrong?

When the ABS light comes on, it will set a diagnostic code that describes exactly what the problem is. So if you find out what that code is, you can troubleshoot the problem and fix it. This is very much like the service engine light and the diagnostic codes that it sets.

Now the issue is that only a select few scanners can check these ABS codes. Most garages have them, but the common backyard mechanic typically does not. So your best bet is to ask a garage to retrieve the ABS coeds and tell you what is wrong. Most place will charge like $10-$20 for this. Then, if you want to fix it yourself, you can.

Originally Posted by m1sterb0b

Does the light have to be on when they test it, or can I bring it in any time? Because like I said, I never know when it comes on!

Just make sure it has come on recently, like within the last week. It does keep a history, but it will clear out after so long. So make sure it was fairly recent that the light was on. But no, it doesn't need to be on when they scan it.

Originally Posted by minichopper6hp

just asking b/c if you have a tire that has alot less tread than the other, it will set the light as that wheel will be traveling different speed than the other. It usually will set the light after driving for a couple of minutes and reset when you turn off the car.

But this isn't typical. I have had tires with very different tread on my car before in various states, and never once did it set the ABS light.

Typically, the ABS light in this situation is going to be caused by a bad WSS or bad wiring.

Originally Posted by Zef_66

But this isn't typical. I have had tires with very different tread on my car before in various states, and never once did it set the ABS light.

Typically, the ABS light in this situation is going to be caused by a bad WSS or bad wiring.

Yep, the abs system shouldn't set a DTC unless tire speeds differ by more than 3 mph. This is done intentionally as when you take corners, the outside tire spins faster than the inside which doesn't set a DTC. Make sure all the contacts in the abs wheel bearing harness connector are mating to each other. A lot of times the female contact gets smashed flat which still makes contact, but when you hit a bump/ect it loses connection for a split second which turns on the abs light.

speaking of tires.........I had a flat, when I put on the spare the TCS and ABS lights lit up just an FYI.

abs module is not cheap!

Originally Posted by m1sterb0b

I took it in, got it scanned for 39 bucks. It shows that "random" codes were coming up. The mechanic said that the sensors looked really good, and since both traction control and abs were messing up that its most likely an ABS Control modual (the brain that controls the ABS). If its not that, then its going to be the abs module it self.

Now, I know where the abs module is (its right next to the master cylinder) but where is the control module. How much will each of these parts cost?

Whoa....you paid the guy $39 and he didn't even give you a description of the codes that it is throwing? Not to mention that anytime a wheel bearing or sensor goes bad, it will throw on the ABS and TC lights since the TC relies on the readings from the sensors to work properly. So a bad sensor or bearing will shut down the TC.

But regardless, it will still have codes set that he should have gave to you, because that is what you paid him to do. Then you can do your own research and find out what is going on. But now, you paid him to give you his opinion. And I wouldn't put too much weight in just one opinion, yours, mine, or anyone's.

Originally Posted by m1sterb0b

I took it in, got it scanned for 39 bucks. It shows that "random" codes were coming up. The mechanic said that the sensors looked really good, and since both traction control and abs were messing up that its most likely an ABS Control modual (the brain that controls the ABS). If its not that, then its going to be the abs module it self.

Now, I know where the abs module is (its right next to the master cylinder) but where is the control module. How much will each of these parts cost?

Don't know if this will help or not....my car is a 2003 and yours is a 97, when I had to replace my ABS module the controller/computer was bad.
The unit itself is the pump and the controller and they are bolted together.
The pump is aluminum with the brake lines attached and the controller is black with a wiring harness attached.
You can see in the pic next to the intake, the label that says "for assembly only" with RB and a barcode below that......that black plastic houses the controller of the module the wiring harness is on the bottom .



It is an expensive part that the dealer wanted more than $1,500.00 for the entire unit.
I tell everybody that has had an ABS module issue here call Ed Morad he sells used GP parts and he might have a replacement for you....I paid $175.00 shipped to my door and that price was for the entire unit, pump and controller.
I don't know what the module for a 97 looks like but it should look very similar I would think.
Hope it helps you