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ABS and Trac Off lights



Speedy1973 said:
just got it on a scan tool the other day, came up with Left Rear Hub and Speed Circuit Assembly, and after that, my transmission is now shifting very slow between every gear, idk what i'm going to do with this thing
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when my hub was acting up, the car would feel funny too. mine would trip the light as the abs check was happening, if the abs light went on the car almost felt like the brakes were holding the car back, or even maybe the trans. i'd turn it off, and re start it and if the light didnt come back the car would still feel like it was holding back, then just let go and drive normal. very odd crap comes with a abs light.

changed my front hub that had a ton of play in it, and no light since.
 
yeah. with my abs light on, of course my ebcm was bad, and since it uses the speed sensors to determine how to use magnasteer, the steering on my car would be really stiff with the lights on
 
Scanners don't tell you "Exactly" whats wrong. Thats where the person looking at the information needs some experience to be able to spot problems. I saw alot of brand new wheel hub assys being replaced for no reason because the code said R front wheel sensor, GM had a big service campaign for the defective wiring harness. More often than not some diagnostics need to take place, Ohm out the wiring and the sensor, checking grounds. A good scanner is only as good as the dude looking at the information.
 
I used the scanner on my car too and it said that the control module was bad. I didnt want to apend over $200 so i looked at the wire harnesses on the left and right axles and found both wires had been broken clean through and had been rotting out all the way up the harness. i just spliced in some new wires and the abs and trac light went off and havent come back on.
 
So I Just replaced my bad hub (fixed the problem 100%) was nice i got a deal on the part too, but one get one 1/2 price, so new wheel hubs in the a$$ end of the prix
Will post up a How To* in near future for other members

Now on to the trans swap in the near future
 


GT2001 said:
I used the scanner on my car too and it said that the control module was bad. I didnt want to apend over $200 so i looked at the wire harnesses on the left and right axles and found both wires had been broken clean through and had been rotting out all the way up the harness. i just spliced in some new wires and the abs and trac light went off and havent come back on.
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Yep... same thing happened to me. Interesting it was one wire that "rotted" pretty much all the way to the ABS module. Spliced in new one problem went away.

Wondering if there is something defective about the wire insulation they used....
 
ronmexico said:
Yep... same thing happened to me. Interesting it was one wire that "rotted" pretty much all the way to the ABS module. Spliced in new one problem went away.

Wondering if there is something defective about the wire insulation they used....
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Well most of the cars on this site are 10+ years old.... surely nothing lasts forever is my best guess
 
Did the scan on mine and the codes came up with CO550, CO896 and CO898. CO898's definition was not available on the high-end scaner I borrowed to run the test. The problem is intermittent and I am still going to check the speed sensor harnesses up front. Also, since I used to be a missile tech (another lifetime ago), I plan on getting to the EBCM and checking the integrity of the harness assembly there and then probably checking the ground. The first time the "multitude of errors" came-up on my DIC, I was sitting in 100 degree heat for about 30 minutes with my AC on waiting for a friend. Anybody want to let me know where I might find the EBCM? I kn
 
Okay.....last post never made it to the forum for some reason and was saved in my autosave file????? anyway, here is the current update to my problem.

So I scanned my car......CO550, CO896 and CO898......found definitions for CO550 and CO896.....nothing for CO898. All seems to point to a bad EBCM. Also, I checked resistance at each sensor over the weekend and all were the same. I "spot" checked wires coming from the hubs and nothing out of the ordinary. Could not find the termination point for the harness to check integrity of the harness so I am assuming that my '04 does not have the shorter harness from each wheel like I have read about checking......I could be wrong so please feel free to correct me if I am. Last step is to eyeball the EBCM and insure good connection as the problem is intermittent and now is mostly not working......but sometimes it starts working then stops working giving all the messages again from my DIC which drives me crazy.
 


Well idk if you located the ebcm or not, but it's the black piece attached to the front of the abs module (box with all the brake lines on the driver side).
If your hubs checked out I'd vote ebcm, cheaper to just rebuild and keep yer warranty and such imo.
 
Someone mentioned that a new ABS module ran something like $1500 dollars. Don't know if there is a similar fix available for GM modules, but a common problem on Volvo Bosch (?) modules is bad/broken solder joints on the circuit board on the incoming DC 12V power connections. You can take them out and fix them yourself if you are handy with soldering, or there a few guys who will refurbish them for less than $100, can't recall who they are, but should be easy to find on a Google search. One of the guys doing this will ship you a refurbished module right away on receipt of payment for the service and will then take yours in return to redo for someone else.
 
My ABS light came on, but I believe it was the result of knocking off a brake sensor.

If I don't feel anything wrong should it be okay? I'm gonna scan and see what it says, but otherwise?
 
NinetyEightGTP said:
My ABS light came on, but I believe it was the result of knocking off a brake sensor.

If I don't feel anything wrong should it be okay? I'm gonna scan and see what it says, but otherwise?
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knocking the plug off wont do anything if its plugged back in, car running you pull the plug, the abs light comes on, plug it back in, lights of instantly.

you can try to clean the plugs, and then grease them with di electric grease, and inspect the wires along the lca's for damage.

and test the hubs for play. if you have lots of play theres your abs light.
 


scottydoggs said:
knocking the plug off wont do anything if its plugged back in, car running you pull the plug, the abs light comes on, plug it back in, lights of instantly.

you can try to clean the plugs, and then grease them with di electric grease, and inspect the wires along the lca's for damage.

and test the hubs for play. if you have lots of play theres your abs light.
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What I'm saying is: If the light is on, is that a bad thing? (I don't mind not having ABS or TCS).
 
if you have no bad symptoms, the car holding back or stiff steering, drive a way.

when mine was lit up all the time, i had no symptoms at all, the brakes just locked up, and the wheels would spin if given to much gas.
 
scottydoggs said:
if you have no bad symptoms, the car holding back or stiff steering, drive a way.

when mine was lit up all the time, i had no symptoms at all, the brakes just locked up, and the wheels would spin if given to much gas.
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Steering is a little stiff, but I've been driving it this way since July because I figured it was just the sensor. Could be the hub, though.

I'll check the code and see what's up. Cheap & easy replacement.
 
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