ABS sensor problems
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AudiWorld Super User
Joined: Nov 2003
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ABS sensor problems
Almost immediately after I got the A6 back on the road the ABS system declared the LF wheel speed sensor was bad and disabled itself. However, using VAG-COM I could see that the sensor was still working, at least to the extent that I could spin the wheel and see the value change.
In the process of attempting to remove and clean the original sensor, I destroyed it. It was really seized into the bore. I bought another sensor and installed it yesterday. It was also a really tight fit -- I did ream out the hole but clearly not enough. I replaced the copper sheath and applied plenty of grease, but I suspect that I won't be able to remove this one intact either.
Anyway, the new sensor didn't fix the problem. Using Vag-Scope I can see that both front wheels report similar speeds when I spin up the wheel by hand. So it looks like the fault code is not due to no signal, but an irregular signal. I may have seen traces of this in Vag-scope but it's hard to say -- it could be a sampling error.
So the next step appears to be to pull the axle and clean off the teeth. Any other suggestions?
In the process of attempting to remove and clean the original sensor, I destroyed it. It was really seized into the bore. I bought another sensor and installed it yesterday. It was also a really tight fit -- I did ream out the hole but clearly not enough. I replaced the copper sheath and applied plenty of grease, but I suspect that I won't be able to remove this one intact either.
Anyway, the new sensor didn't fix the problem. Using Vag-Scope I can see that both front wheels report similar speeds when I spin up the wheel by hand. So it looks like the fault code is not due to no signal, but an irregular signal. I may have seen traces of this in Vag-scope but it's hard to say -- it could be a sampling error.
So the next step appears to be to pull the axle and clean off the teeth. Any other suggestions?
AudiWorld Super User
Joined: Aug 2005
Posts: 4,904
Likes: 2
From: beside the Great Salty Wetspot
do you have another ABS control module you could swap in?
and check the electrical connector on the one you have, at least. Maybe trace the wire back to the module to see if it's damaged anywhere.
I had a 1995 that I never could sort out. One sensor kept throwing a code. I replaced the sensor with a used one...no help. My next step would have been to swap the control module when I found a used one...but I sold it before that.
I had a 1995 that I never could sort out. One sensor kept throwing a code. I replaced the sensor with a used one...no help. My next step would have been to swap the control module when I found a used one...but I sold it before that.
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kday
Audi 100 / A6 (C4 Platform)
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Apr 7, 2008 07:40 PM
