2004 Chevy Impala Wheel Sensors for ABS/Traction

My husband works on older models of cars ,and somethings on my car ,He put the brake pads on my car. but he doesn't know anthing about the warning lights and sensors if that is the problem . he has changed motors in chev, ford, dodge trucks .before thanks for any info.

Thank you,I think that will be a great help . I well show it to my husband. Every little bit of information helps. Thanks again!!

G'day,

I do not know the Chevy's system but many traction control systems in Australia use the application of brakes to control wheelspin, similar to stability controls. The brakes are applied as required using the ABS pump and release system.

So, just a thought, replacing the pads may require the resetting of the ABS/Traction Control computer after having the fluid pushed back into the reservoir when the new pads were installed. Check the workshop manual or better still, get the bloke who replaced the pads to reset it or otherwise fix it.

Regards,

Royce

Thank you! I will have my husband try all this , I called a chevy dealer and they said it would be $70.00 an hour to put it on a machine that tells you what is wrong with your vehicle. I just hate to go threw all of that, with the price of food and gas these days.You have to watch every penny. . The brakes work fine .no noise,cracking,or pulling to the side. everything seems ok. But Thanks again!

In my limited knowledge of ABS, (it came after I used to actively repair all my vehicles for everything! I only do the easy bits now like brake pad and disk replacement), something was done (by your husband?) that caused an ABS sensor to give bad signals, it might only be one.

Sometimes the ABS system has a visible (sometimes not visible) circle with teeth cut into the outer edge and a sensor reading off the teeth. It might just be as simple as a cable to a sensor is off.......or it might be actual damage to a sensor or cable. Get him to check.....

Also, did he bleed off the extra brake fluid (good move), or push it back into the master cylinder (bad move)? I always use a piece of plastic under the brake reservoir cap to stop fluid flowing out of being pushed back. I then open the brake bleed screw while pushing the pistons back.....

My guess is that he damaged or moved an ABS wheel sensor. On older vehicles there are only 3, one is on each front wheel and one is in the rear axle, most front wheel drive vehicles today have 4, one on each wheel......but I am sure that there are other versions as well......

Thank you! I will tell him about what you said , And have him check iit out.Thanks again!

One more question. How soon did the warning lights come on after the pads were replaced?

He put the pads on about 8 months ago . I have about 5,000 miles on the brake pads. The brakes work great no noise or anything out of the way. When I start my car there are no lights on. When I put it in gear the service traction system light comes on for about 20 seconds and then goes off , Then the ABS light comes on and stays on .then there is another traction off light that comes on and stays on. I pushed the traction button on and off and the light still stays on. Those 2 lights stay on as long as it is in gear. Thanks for asking! Thanks Roxie

You still did not answer the question as required, let me repeat it so that we know exactly what happened:-

Did the problem start immediately the very first time you drove the car after the pads were replaced (5000 miles ago)? Yes or no......

No , it just started a few days ago

Thank you.

Was someone "Off roading" with the car when the problem started?

Do you have animals where you are, like we have in Germany, that like to bite through cables and pipes on cars?

Has anyone done a full cable check over the car, preferably when its on a lift?

I live in a rural are in west virginia, The car has always been on paved roads. no animals. mostly birds. LOL .He has not done a full cable check yet . The car was in my driveway ,when I pulled out of the driveway the lights came on.

At this moment it tends to look like an animal or "wear & tear"......but lets wait up for the cable check before going any further.....

Andy are you and lyn the same person??? due to you both asked the same guestion. lyn asked first and then andy asked the question,lyn wanted a yes or no answer. then andy said you need to answer yes or no . so you are both the same people, go back and read and please refresh your memory.to whom you really are. thanks

No we are not the same person, but we appear to think alike.......

I actually live in Germany.....I am on a different time zone to most here.....that could have something to do with it.....I will go and look at Lyn's posts after this is closed.

If I WAS the same person, which is as good as impossible (for me totally impossible) on CR4 nowadays, certainly I have no interest in a dual personality, why would I post the same question twice?

If you read the posts chronologically, you will see that Lyn asked the question, you did not answer it accurately, so I asked it in a way that simplified the answers to a yes or a no......

Accurate infos are the only way to go, you were not accurate enough before. Its as simple as that.....

Thanks for clearing that up. and thanks again for youe help.

Not the same person, but they did go to different schools together.

RIGHT!

LOL!!

mamaw56,

I've been away for awhile.

Andy Germany and me the same person? Oh come on! Anyone can see that I'm a quaint, rustic old barn and Andy's well, a dog. Take it back to the shop. They should have never let you leave if the lights weren't out. Good luck.

Your words are very wuff on me!!!

Please paws for thought before answering.

Don't bark up the wrong tree!!

SIT!!

I had the same thing on my 02 Buick Rendezvous. I had the codes checked and they said its common for these lights to come on when one or more of the wheel bearings need to be replaced.

.....or maybe just correctly adjusted? Loose or broken bearings may have a similar electrical characteristic....

Many forget that usually at least the non driven wheels on many cars are using tapered roller bearings that need to be set up with a specific pre-load from time to time.

To test, you need to lever the disc pads off the disk, raise the wheel off the ground and try and move it at 90° to the direction of rotation (waggle!), I usually pick first top and bottom with both hands and then front and back.......there are special test centers here for the bi-annual checks and that is done by a machine......probably better though.

I would have to go along with the wheel bearing theory. A wheel speed sensor must be very accurately positioned to count the ribs on the rotating part at the speeds today's vehicles are capable of. If a wheel bearing is loose, the distance between sensor and ring will change. To test, follow Andy's directions.

If the bearings are loose, you need to replace the bearing assembly. Your car does not have adjustable or repairable wheel bearings. They are replaced as an assembly. This does run the price of the parts up some, but, it is designed to be fool proof. Just remove the old assembly, and bolt on the new part. There is no adjustment to make, so it can not be done wrong. Get a manual and it should not be any harder than front calipers. Good luck.

I'm going to take the car to a garage today and have them put a hub assembly on both front wheels. I hope that takes care of the problem .I'll let you all know if that helps. Thanks for everyones help. You guys have been great. Thanks Again!

It may not be a front wheel bearing. Tell the shop of your concerns, and force them to decide where the bad wheel bearing is. If you guess wrong, you pay. If they guess wrong they eat it. Good luck.

There is not enough space on this system to detail what could be wrong. Save yourself some grief and take it to an automotive electronics specialty shop, Gm dealership or highly rated independent repair shop. Now finding one that is actually honest, totally different deal. Angies list, check it out.

∑ Sundog

I just went and picked up my car. He told my husband and I that all 3 lights are still on .He showed us the old parts he took off my car ( hub assembly). He put both sides on. He checked the back hubs,and they are alright. He told us the front hubs were worn out . Everything checks out okay. I drove it 12 miles back home and the 3 lights are still on. Drives just like it always did.Let me know if you can think of anything else it could be!

Speed sensor. It may have been damaged by the bad bearings in he hub.

I also had the speed sensor put in , the lights use to come on after i put it in drive and started driving.Now when I start the car they come on and stay on like before.

If I understand you fully here:-

Before, the lights only came on when you put the car in drive. Now they come on when you start the engine and then stay on as they did before....

So in fact (if I understood you correctly) the problem is now worse!!!

If that is not exactly correct, please correct your statement once again.

If what you wrote is not at least 100% correct each time, the help we are able to offer will be not as good as it could be.

My personal take at this time is that you need to go to the car manufacturer and get a professional opinion and readout or the car computer.....

Andy you are right ,the lights use to come on when I put it in drive . now they come on just when it starts.

Go and pay for an hour of diagnostics, then decide what to do....

OR

That does sound like a broken sensor that is checked BEFORE driving i.e. at motor start time.

Check each sensor with a torch as best you can......remove and compare each one to each other for one that has different characteristics using the MK 1 Eyeball and then an Ohmmeter....

Hi bobc,

may I make a slight alteration for the sake of clarity (hopefully I understood you correctly!), you wrote:-

Speed sensor. It may have been damaged by the bad bearings in he hub.

Did you mean?:-

ABS wheel sensor. It may have been damaged by the possible "play" in the bad bearings in he hub.

Sure, that's easy for you to say.

Yes, that is what was in my mind. If there was play, the ABS speed sensor may have rubbed against the teeth on the rotating hub.

I am not an expert on the fine points of the ABS systems, but, if the system only lit the lights when the car was put in gear, It was because the computer did not see the signal from the speed sensor that it expected when the wheel moved. But, if the light is coming on now before the car moves, I would think that there is another problem. Could be a bad connection, blown fuse, something like that. My experience has been that the wheel speed sensors will not trip codes till the vehicle moves, unless it is left unplugged. Just my 2 cents worth.

What you say fits in with my limited knowledge as well.....

You need to go to the manufacturer to get the codes cleared out and to then see if they repeat again. Its normal today. Any reputable car repair dealership can erase the code storage so that you start from new again....

The man at the garage also told me that te rear hubs are ok . Would the lights all come on if the car needed rear hub assembly. He told us the the sensors all came with the from hub assembly. Thamks again for everybodys help.

I suspect that even if ONLY one sensor sees and error, you will still get all the lights!!!

I assume you have 4 sensors by the way.....