Brake warning light came on. Diagnosed as bad abs module. Mechanic replaced twice. One shell sensor continues to read not turning while it is turning. Mechanic has check continuity, it’s fine. Seems to have a short. He cannot find where it is and next step is ripping out much interior to track tiny wire. Will not pass state inspection with brake warning light on. Help. ps I do not trust VW dealer, some bad experiences. Help help!
This is such a common occurrence with VWs as they age that there is a whole cottage industry devoted to the rebuilding/modifying of VW ABS Modules.
Here is one company that provides this service: http://www.modulemaster.com/en/Volkswagen/process_vw.php
However, there are others that you can locate via a Google or Bing search.
could be as simple as bad ground wire for abs module. run a new ground wire.
You may need to find a mechanic that has the equipment, like an oscilloscope, to read the signal from the wheel sensor to make sure it is 1) generating a signal and 2) the signal is reaching the module. If the signal is being generated at the sensor, but not reaching the module, I’d clip that wire and put a jumper wire in it’s place. I would definitively determine the wire was bad before clipping it, but that sure beats ripping the interior out and opening up wire harnesses.
What state do you live in? I know that here in NY state an ABS light will not fail you. I had a 2002 Town & Country that had the ABS light on for 4 years and never failed inspection. My other car at the time was a 2004 PT Cruiser that didn’t come with ABS (one of the reasons I bought it) .
Here’s what I would do
Backprobe the sensor wires all the way at the module. Spin the wheel. If you get a good clean signal at the module, you’ve proven that the wiring is good.
If the original module has been kept, it may well still be ok. You might can save some money by returning the two modules and installing the original. I’m saying maybe just the wire was the problem all along. Replacing a bad wire with a good one may well fix the original problem. And it shouldn’t prove to be a very difficult thing to replace a wire. Finding where the existing one is shorted or broken is difficult, but no need to do that. At least I don’t see a reason. I agree that this is not a problem for a dealer, best to use an inde shop that comes well recommended and preferably specializes in VW’s or at least German cars.