Within the last two weeks, my '04 Cav LS has been having this weird issue where I occasionally get 3 warning lights in the dash: ABS, Service Wrench and Trac Off. It doesn't happen all the time, only the times where I don't have the time to get the code checked. It seems to happen more when the car is in reverse, and if I stop and re-start the car, the lights go away, and the car seems to hesitate a little before starting up. I got the battery checked over the weekend and its still good. Even with the warning lights on, there is no noticeable difference in acceleration, braking, handling, etc.

I'm thinking a bad ABS sensor, but I've been wrong before. I'm hoping I will be able to get the warning lights to come on when I have enough time to go get the code read. Any help is appreciated.

Check the front wheel speed sensor wires, they are junk and fall apart on these cars. Follow the whole harness and give them a little tug you will find it will pull apart somewhere. Happened on my car easy fix

even if the light isnt on, the code should still be stored in the memory for a certain amount of time. go try and have it read.

So, finally got the code checked out... except there is no code... Next, I'm going to take Alex's advice.

are they just using a basic code reader? light illumination means codewith the service light.

Alex Currington wrote:Check the front wheel speed sensor wires, they are junk and fall apart on these cars. Follow the whole harness and give them a little tug you will find it will pull apart somewhere. Happened on my car easy fix

can you elaborate on this?



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The wires are easily damaged. Usually by the knuckle or where the control arm meets the cradle.

is it on both sides or just one?



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Find your wheel sensors (look for a single heavy gauge wire coming from the wheel spindle.) start tugging, firmly but dont yank like yer pull starting the lawnmower . tug at everything as far back as you can. There may be a very slight break in the wire thats causing and intermittent issue.

Makes me wonder with the Traction light coming on as well there is a high possibility that it is your ABS pump failing as this is what also controls your traction. Get too an area and get the car up too 60-80 km hr or 40mph ish and brake HARD stand on that pedal till you stop do this 3-4 times as it will forst the ABS pump to work. if the ABS light comes on then stays on..... your pumps on its way out.

Yes sometimes a code can come up but for whatever reason computer doesnt show it. I've experienced a lot of the time ABS codes dont hold in the system, if that ABS light doesnt stay on it doesnt log the issue.


Best of luck as I've replace and ABS pump and it cost me 1200 dollars (92 cadillac)

ok ,so apparently no technicians like myself has chimed in on this yet. First to vincent's comment about abs pump, thats not likely. The abs and traction control system are linked together , always in my experience both lights come on together because they both use signals from the wheel speed sensors to work. The wires going to the front sensors on these cars are very common for breaking or corroding. When these codes come on you need to drive the car till the light comes on and then without shutting it off scan the abs computer while the light is on and it will then show a fault code. Usually it is in the wire where it routes across the lower control arm , i have seen more on right(passenger side) than anything. Another way we have got the light to come on is raise it in the air while running and have another guy move the wires around. If it is bad it will set the light off while doing so.To repair this problem i recommend getting the doorman abs pigtail and using solder with shrink wrap to fix it. I have fixed probably a good hundred or so of these on several gm cars. Let me know if you need anymore assistance or part number for pigtail.

Todd Haworth wrote:ok ,so apparently no technicians like myself has chimed in on this yet. First to vincent's comment about abs pump, thats not likely. The abs and traction control system are linked together , always in my experience both lights come on together because they both use signals from the wheel speed sensors to work. The wires going to the front sensors on these cars are very common for breaking or corroding. When these codes come on you need to drive the car till the light comes on and then without shutting it off scan the abs computer while the light is on and it will then show a fault code. Usually it is in the wire where it routes across the lower control arm , i have seen more on right(passenger side) than anything. Another way we have got the light to come on is raise it in the air while running and have another guy move the wires around. If it is bad it will set the light off while doing so.To repair this problem i recommend getting the doorman abs pigtail and using solder with shrink wrap to fix it. I have fixed probably a good hundred or so of these on several gm cars. Let me know if you need anymore assistance or part number for pigtail.

isnt that what I just said?? But this guy most likely cant afford to buy a 300 dollar live scanner as you cant just plug in a typical OBD reader with the car running as you run the chance of screwing the computer, as most have blatant warnings not too do that or usethem on a running car. I gave him options to eliminate his ABS pump, and to say its unlikely is a bit off when thats exactly what my cadillac was doing when the ABS pump failed. One of the ABS Sensors as well may have dislodged and even moved that1/16 of an inch to far from the effect wheel. If you cant figure out what the issue is after all these suggestions and rarely brake hard enough to engage your ABS and know how to drive without it... let it go. As well as hard braking I suggested to get the pump activating, try to get your traction to engage, ie spinning on some light gravel this time of year.



I may not be ASE certified but I've worked in a shop for 2 years and on my own for 5, I quit working in a shop cause I have a really hard time dealing with people. Stuff that I think is common knowlege isnt.

Vincent no offense ,but no i didn't say what you said and u are spouting off untrue info. First of all if your abs and or traction light is on your abs is disabled, so slamming on your brakes will not engage the abs. Second of all of course u had a problem with your cadillac beacause they are junk! I have been working pro on cars for 10 plus years in reputable shop and never have i seen a bad abs pump on a cavaleir.And i am ASE certified in several catagories including brakes. As far as running your car in the air it wont hurt a cavalier or most other cars either. If you actually worked on cars u would know mechanics run cars in the air all the time to find noises, especially wheel bearings and such.

What on earth does running your car in the air have to do with anything I never said anything about it? Every mechanic I know as well as myself, road tests a vehicle as most noises are prominent while under load such as CV Joints. We have two great long stretch hills in town that work marvelous for this.

As you must know a proper technician will diagnose EVERY option otherwise they are just a parts changer. Theres 2 shops here in town like that, its horrible. Yes if the ABS and Traction are on the system is bypassing. He has an intermittent problem and road testing as suggested forces every part of the system to function. it may only be a wheel sensor but he doesnt regularly apply the brakes hard enough to engage the ABS, thus it only comes on occassinally becuase for some reason the system tried to function but the bad wheel sensor said nope not gonna do it. by getting it up to speed and brakeing hard to a stop if a wheel sensor is out, when the ABS tries to work and that sensor fails theres a good chance that the bad sensor wheel is going to lock up first.... TA DA problem found. (is it just me or was that a really bad run on sentence. I didnt do well in english class) Or onthe flip if its the traction thats causing it, get the wheels to spin.

If he could afford a live scan tool www.scantool.net he could run it constantly and figure it out.