ABS issue

Tiny
BEAT KID
  • MEMBER
  • 2005 CHEVROLET CAVALIER
  • 2.2L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 122,800 MILES
To make a long story short, a little more than a week ago I installed rear shims on both sides because the toe was off and I aligned it and it straightened out the rear (note: there were shims already installed but were removed and installed with the corrected ones) a week later my ABS, trac off, service wrench and brake light all come on. Its very random timing as well. Usually first the ABS, trac off and brake light will come on, then randomly the ABS and brake light will go out and the service wrench will come on but the trac off just stays on. Then randomly the ABS and brake light will come on. So it basically starts with three lights (ABS, brake, trac off) then randomly switches between two lights(service wrench, trac off) and four lights(ABS, brake, trac off, service wrench). History codes are c1234, c1235, u1000, u1016. Diagnostics has been hard to do because the lights switch randomly so I have not been able to capture current codes but I did do data display with service wrench and trac off lights on and all four sensors were reading and I tested both rear connectors and got 4.74 volts on each side. It seems to be more active when it rains out. My question is could the shims be causing the rear ABS to be wonky or does it sound more like a wiring issue? This car had shims in it before and never had issues. Thanks
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Monday, September 12th, 2016 AT 8:11 PM

5 Replies

Tiny
HMAC300
  • EXPERT
See picture for causes. These wires are very fine and may be broken or getting wet when it rains. Your voltage is too high. I kind of doubt the shims did it unless the sensor have moved farther away from sensor ring. For the u codes a mechanic is going to have to look to see which module is not talking to the other.
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Tuesday, September 13th, 2016 AT 9:36 AM
Tiny
BEAT KID
  • MEMBER
Thanks for your help its much appreciated, today I was able to drive with a modus plugged in to monitor the abs and I noticed when the lights came on I lost communication and when its just the two lights it can communicate but when all four lights are on it stops communicating so now I can look into your suggestions and worst case narrow it down to the computer which does not seem uncommon on forums. Thanks again!
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Tuesday, September 13th, 2016 AT 6:48 PM
Tiny
HMAC300
  • EXPERT
Well it should be checked with a pro scanner just to make sure because it may be something like a poor connection, try putting dielectric grease on abs connection at unit.
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Wednesday, September 14th, 2016 AT 6:37 AM
Tiny
BEAT KID
  • MEMBER
Connection seems fine and I checked power and ground, did try the dielectric grease and drove it and still have issue so I know what the last step would be but one last question for you would be is there a specified voltage for the class serial data lines if im checking it with a meter at the ebcm connector with the KOEO?
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Friday, September 16th, 2016 AT 4:50 AM
Tiny
HMAC300
  • EXPERT
No because the serial lines are one module talking to another and I really don't know how to check that with a volt meter and you need to know the code where to start anyhow.
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Friday, September 16th, 2016 AT 6:19 AM

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