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Hey guys,
I’m currently trying to figure out some issues on my aunt’s 05 Terraza. She says that occasionally when making a turn the traction control light will pop on. I had it for a short time today and checked the codes. It had C0035 and C0036 for left front wheel speed sensor (WSS), C0040 for right front WSS, C0253 for centering malfunction, and C0281 for dynamic rear proportioning (DRC) performance. I was able to recreate the issue once. When backing out of a parking space at low speed with wheel somewhat turned, the TCS made the buzzing sound for about a second and the traction control light popped on for a few seconds. That’s the only time it happened to me.
In my garage after that, I pulled the wheels off and visually inspected both WSS harnesses. The connections were very clean, but I put some dielectric grease and reinstalled them. I traced the wiring into the engine bay and visually inspected it. I removed the airbox to check the wiring that goes under there across the transmission, and it didn’t look chafed or out of the ordinary at all. I also visually inspected the wiring coming through the firewall to the EBCM under the wiper motor arms and they seemed fine. I cleared the codes and was not able to replicate the problem again and the codes didn’t pop back on there while I had it. Just wondering what my next move should be if she continues to have issues. Also wondering because of the C0253 if it has something to do with the steering wheel position sensor.
Thanks,
Charlie
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Replies
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Speed sensor wiring tends to break somewhere on or near the suspension, pull the loom back as far as you can to inspect it. If the sensor itself can be removed you can try removing it and using a flat file cleaning the surface it tightens onto, rust and corrosion can build up moving the sensor just far enough away from the exciter ring (the proper name eludes me) that it loses signal and sets the code. Pretty common on GMs.
If there was ever an alignment performed and the SAS wasn’t reset to zero that could likely be the culprit.
If you’ve cleared the codes and they haven’t come back, then perhaps it was an intermittent issue. If the codes and symptom come back however, I would be looking at the speed sensor signal. The best way to view this is with a lab scope. Not everyone has one of these. A DVOM won’t cut it, it’s not fast enough to see anomalies in the signal. In addition you also want to check the tone ring if it’s accessible. Damage to a tone ring can also cause that issue. As for the steering sensor, that may also be an issue. If that code comes back, you might consider replacing it.
Good luck and keep us posted.
So without a lab scope, I wouldn’t be able to check speed sensor signal? What about checking reference through the speed sensor wire? Now that I think about it, it would make sense that a steering sensor is causing the issue wouldn’t it? By receiving the incorrect signal from the steering sensor, it would turn on the traction control system during turns, correct? I know I have a lot of questions, but I’m only 22 and have only been actually wrenching (not including oil changes and brakes) for about a year now. I’m trying to learn as much as I can and your videos have been great for that. I know I speak for everyone when I say thank you very much for what you do; it’s a great service.
If the error is intermittent, no a DVOM will not be fast enough to catch it. However with the vehicle properly jacked up and in neutral you can set your DVOM to AC and test at the sensor to see if it’s producing a signal by rotating the wheel. You wont see a signal pattern but you should get some sort of a reading, being that it’s a GM there should be a connector at the sensor. I think that made sense.
Hello all. Sorry for the delay! All I ended up doing at the time was pulling the connector off the ABS sensor on each front wheel, put some dielectric grease in the connector, and put it back together. Its been about a week and a half, and my aunt told me the problem has not happened again since I gave it back to her. She told me the ABS light has not come back on since then either. So as of now, I would say the problem is resolved. Thanks for the help everyone.
Next time, pull sensor itself out and spray clean with brake cleaner.
http://www.audipages.com/Tech_Articles/susp_whls_brake_steer/absrepair7.JPG
http://www.volvoclub.org.uk/faq/ImagesProcedures/ABSWheelSensorA.gif
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