2007 Tahoe ABS Light On - Can I fix?

[rnorman4]

Hi all, my hoe was intermittently showing the ABS light (+service traction control message and stabilitrak light/message) and now it's permanently on...Is this something I can fix? I'm thinking it might be one of the sensors at the wheels? If it is most likely this, can an average back yard mechanic repair/replace the sensor? Is there any write up here how to test the sensors?
THanks,
RN

 

[clkelley]

Yes Sir, you can attempt a fix yourself. Start by simply removing the front wheels and brakes to gain access to the hub bearing assemblies on each side. Once you can see the sensor on the top of the hub, the most common cause for these issues would be corrosion on the top of the hub bearing separating the sensor from the magnetic gear inside the hub. What you want to do is remove the sensor from the top of the hub bearing assembly, sand or grind on it just until it is clean metal, then paint it with a VERY THIN layer of corrosion resistant high temp paint and reinstall the sensor.

Try that and see if it helps. To help a little more, I have included a link below to DIY Pics of me fixing an older version of the same issue on my 03 Duramax, yes it is a different vehicle but the basics are the same, and if you view the individual pics they have descriptions added so that you can know what is going on in each pic. Try it and see if that helps at all.

http://s278.photobucket.com/albums/kk102/bigdaddydiesel_photos/Truck%20projects/GMC%20Chevy%202500HD%20Front%20ABS%20Sensor%20Change%20Service/

 

[rnorman4]

Thanks CLKelly, that's a good post and pictures for sure. I'm going to start this job tomorrow. Will post on how it goes.
RN

 

[rnorman4]

Got it fixed.

After some reading on how these sensors work, I devised a test using an oscilloscope (not many people have one of these sitting around I guess). I found one bad sensor (i.e. no output waveform on the scope while rotating the wheel hub). I figured this was the problem, went and bought a new aftermarket sensor ($152) (which came with the hub and bearing for cheaper than buying the sensor alone from the local GM dealership ($300). Plugged in the sensor and all the dash lights (check traction control, check stabili-trak, ABS...) went out. I ran the truck down a dirt road and jammed on the breaks and the ABS works fine. A couple of pictures attached. These sensors are "hall effect" as far as I can tell, with an integrated circuit that controls the gain of the sensor and outputs pulses, this requires +12V and gnd from the screw that holds the sensor in place, the return wire is signal. I measured from signal to +12V but the output from signal to gnd was probably higher.

Need more info? post reply.

RN

 

[starsailor]

Yes Sir, you can attempt a fix yourself. Start by simply removing the front wheels and brakes to gain access to the hub bearing assemblies on each side. Once you can see the sensor on the top of the hub, the most common cause for these issues would be corrosion on the top of the hub bearing separating the sensor from the magnetic gear inside the hub. What you want to do is remove the sensor from the top of the hub bearing assembly, sand or grind on it just until it is clean metal, then paint it with a VERY THIN layer of corrosion resistant high temp paint and reinstall the sensor.

Try that and see if it helps. To help a little more, I have included a link below to DIY Pics of me fixing an older version of the same issue on my 03 Duramax, yes it is a different vehicle but the basics are the same, and if you view the individual pics they have descriptions added so that you can know what is going on in each pic. Try it and see if that helps at all.

http://s278.photobucket.com/albums/kk102/bigdaddydiesel_photos/Truck%20projects/GMC%20Chevy%202500HD%20Front%20ABS%20Sensor%20Change%20Service/

So what's the goal with this procedure? Are you trying to reestablish a path to ground thru the bearing ass'y by cleaning the corrosion under the sensors, or are you trying reinsulate the sensor from grounging out on the bearing ass'y.

 

[rnorman4]

clkelley will probably answer you...

When I took the sensor out I found no dirt etc... on the sensor end, it was just dead for some reason. The rear sensors were different then the front.

 

[clkelley]

The purpose of the service is to reestablish the link between the sensor and the magnetic gear on the inside of the hub bearing. The corrosion on top of the hub bearing can cause just enough separation between the sensor and the magnetic gear so as to cause a failure in the sensor. That is part of the reason why, when folks experience the light coming on, it is often intermittent instead of staying on all the time, at least at first.

 

[gjs7]

TRy replacing a terminating resistor in the wiring harness (by the spare tire).

 

[selfmade]

Crazy dash lights

I called dealer to obtain terminating resistor, but they acted as if that didn't know what I was talking about. Where can I purchase the resistor from

 

[Rd05lly]

I called dealer to obtain terminating resistor, but they acted as if that didn't know what I was talking about. Where can I purchase the resistor from

Old thread Maybe start you own thread and tell us what your tahoe is doing and might be able to help more