Abs Active Handling !!?!!
It should be upfront... i can't think of why yours would be located in the back. Check the link posted directly above mine and ready through there. Bill is good people.
It could just be a grounding issue or as nmp stated it could besomething werid like your wheels sensor, but the fact that you lost the use of your brakes probably means it's something more than just one sensor. I still think based off the commmon problem with the EBCM, i'm going to guess the problem is either the the EBCM it's self or a ground leading to it which would also mess up the EBCM. Check out the other thread and see what you get.. But ya.. it should be located in the front.
Thank you.
Sorry for the confusion NOS.
as for how they fix it in a day....
I'll guess it' like a handful of other GM electronic board problems.. Probably bad solder.. 5 min job at best for the experianced... Just a guess....


