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"abs" and "trac off" lights staying on?

J

john9472

New member
Hello,

my "abs" and "trac off" lights stay on about 50% of the time. They generally come on soon after (or at) start up and stay on until I shut the car off. I also experience my brake pedal crunching or going soft at slow speeds (below 30 kmh) about 30% of the time as if the abs system is becoming active. I have just replaced the pads front and back. Any ideas? Thanks.
 


I would say that you have a bad wheel speed sensor and need to replace the hub. Or you have a bad wire somewhere, but I would put my money on the hub.
 
Thanks for your reply!! I know very little about cars. I checked prices online (Advance Auto Parts) and it looks like hubs are $89 each. Would I need to replace all four? 89 x 4 plus labour ouch! Could I just drive the car the way it is or should I get it fixed.

FYI: I have 322,000 KM's (about 200,000 miles) on my car hoping to get to 500,000 kms or more.

Thanks, John.
 
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If your ABS is cutting in when it shouldn't be, I'd get it fixed. When someone in front of you slams on their brakes isn't the time to be wishing yours worked properly.

I doubt all four are bad. I'd check the wiring first, then see if you can get it diagnosed at a shop (or find someone here who knows how) to see which one needs to be replaced.

For replacements, try Ed Morad.
 
The ABS stores codes about the performance of the brakes much like the engine does when a Service Engine Soon light appears. With the appropriate computer scanner, these codes can be read to determine what is wrong. If you can find a shop that can read these ABS codes, that will tell you which wheel bearing is going bad. All four do not need replaced, just the bad one.

So I would start by trying to find a shop that can read your ABS codes and tell you what is wrong.
 
I am also encountering the same problem. I just had my two front hubs replaced about 5 months ago. I bought them from Advance Auto Parts. They were Federal Mogul ($125.00 each). I guess a wire must be loose or it would need replacement. Perhaps defective???
 


its possible that it's a bad connection at the connector on the hub, or at the "frame" end of the harness that goes to the hub.
 
I will be taking my car in to have it looked at on my next oil change...I will let you know what they find when they hook it up to the computer. Question for Burgandyman: once you replaced the two front hubs are you still experiencing the problem?
 
FWIW guys, I have not had good luck with aftermarket new hubs. Most recently, I replaced a bad wheel bearing with a new one from NAPA ($140). After about a year, less than 30k miles, it went bad again. It was making noise and had play in it.

From then on, I will only replace bad hubs (and most other parts) with genuine GM parts. I get most of mine from Ed Morad (Morad Parts Company - 3800 Motors, Transaxles, & Stock Parts). But the way I figure, I pay $100 less for a part that is used, but still going to last me longer. One wheel bearing I have in my car now is a used GM unit and I have put over 60k miles on it. Just not worth it in my mind.
 
To be honest I really only replaced the two front hubs, because I suspected that they might have contributed to a humming noise during acceleration. In fact, this was not the problem. So I just left the new hubs on. To date, I still cannot tell what causes humming noise during acceleration. It almost sounds like a subtle thump. I had installed brand new Goodyear H2 tires. GM still cannot detect any noticeable problem. The axles are fine. No leaks, no noises.

Now to the ABS problem. I had GM look at it. They indicated that the rear ABS might be faulty. There was no loose wiring or connector issue. GM charges 200 for the rear hub bearing (even with my corvette club discount)...Advance Auto Parts charges me $110 for their high Federal Mogul Hub Bearing with my corporate discount. Given Zef_66's post. I might have to return to GM OEM parts. I hate to part with $200. I would think that Federal Mogul Bearings are fully compliant (comes with two year warantee). This is their bread and butter. Any thoughts?
 
Burgundyman said:
Any thoughts?
Click to expand...


As I said above, I have had good luck with parts from Ed Morad. I think a rear hub is like $30-$40. But not everyone is comfortable using used parts.

And this is just my opinion. I am not a mechanic. So take it for what its worth.
 


I have the same problem on my GP, i had a friend of mine who is an ASE certified mechanic (that worked at a pontiac dealership) tell me that my ABS sensors had pretty much grinded down to almost nothing and would have to be replaced with the wheel hubs. once sensors and hubs are replaced, the computer can be reset and the SES and ABS lights will go out, as well as traction control will function again.
i had the hubs replaced, but the previous mechanic (not this one) torqued the bolts down too hard and grinded away the hubs again. so now im on my third set of hubs, and no problem this time. just need new ABS sensors.
 
agent505 said:
I have the same problem on my GP, i had a friend of mine who is an ASE certified mechanic (that worked at a pontiac dealership) tell me that my ABS sensors had pretty much grinded down to almost nothing and would have to be replaced with the wheel hubs. once sensors and hubs are replaced, the computer can be reset and the SES and ABS lights will go out, as well as traction control will function again.
i had the hubs replaced, but the previous mechanic (not this one) torqued the bolts down too hard and grinded away the hubs again. so now im on my third set of hubs, and no problem this time. just need new ABS sensors.
Click to expand...


I have never heard anyone say anything about this problem. What bolts did he torque too hard? And I can't see any way that this would even cause a problem?

I bet your mechanic is feeding you a line....
 
Im having a similar problem in my 97 gt. Execpt sometimes my car dies when I press the brake. The ABS light (sometimes, and then right off after the car dies) and the check tire pressure is on all the time. I can understand the hub going bad. it has over 100,000 on it but why would it cause the car to die? any ideas?
 
believe it or not im havin the same problem and took it to the shop and i got under it and the damn left side cv joint is bad so im waitin on Orielly's to get it from there warehouse then i should be good....just another suggestion it could be be ur cv joints guys....
 
I also am seeing this on mu 02 Grand Prix and the research I have found points to cleaning the ABS sensors for a cheap possible fix... I am going to try this today.
 


Holy "can't see crap" Batman: I pulled the front calipar and rotor and still can't see the sensor. On the back side all I see is the wire: :th_scratchhead:
I'm not brave (AKA Stupid) enough to pull the hub assembly so off to the rear and I see the sensor from the back side but it does not appear it will pop out from the back side, but you must remove the "drum/rotor" to get a peek at it; :th_tongue2:
I think I'll leave this one to a mechanic...
 
The abs sensor is inside of the hub, you can not clean it. Take the electrical connection apart and see if it is in good shape(making good conection) if it looks good put some die electric grease on the connection. Take the split loom of of the wire on the A-arm and make sure the wire is not cracked or frayed. you can also hook you car up to a scanner to see whitchwheel bearing is not readin it might not even be the corner you changed the half shaft on.
 
I hope you all don't think I hijacked this thread, but to answer "specialeditiongtp" I actually had a garage replace the front hubs. Since these sensors are in the hub should I assume that the sensors are new also? I hope so...
I was reading on a couple of web sites when I goggled GM brake sensor and found that some are cleanable. Evidently the 02's are not.
 
Yes if you got new hubs they have new sensors in them, If your abs light still comes one, you either have a bad conection, or a bad wire, or one of the rear hubs is bad, I would check the conections and wires first. If you have acess to a scanner hook it up, and you can see exactly what each hub is reading.
 
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