jschick

I just bought a project 99 A4, this is my first A4 but I have had several A6's and worked on other A4's. the ABS light is on and the Brake light blinks. i went to pull codes last night and I get no connection with the controller?? all other functions work on the Vag ad I have the original Vag cable and newest version of SW.
My owners manual shows 2 fuses for the ABS, one normal size fuse and one Mini fuse, the mini fuse is good but I do not have the normal size fuse and their is only one wire in the socket, so either the car doesn't have 2 fuses or someone pushed the wire out of the fuse boxsocket??

I am assuming I must have a bad module, or bad wireing? So where are the components located on the A4? and any ideas where to start? I am guessing the flashing brake light is for the fluid level which is full so probably a bad sensor?

any tips or ideas? i have never run into a problem where I can't communicate with the car????

jschick

well I searched thru modulmasters and looks like the module is fairly a common failure on the A4 and one symptom is failure to communicate, so looks like that may be it.

But they also state that if the ABS, brake light and warning beep come on at the same time it is a power issue? so can anyone confirm the 99 A4 uses 2 fuses??
are their any other control modules or issues with the A4 ABS to check into? or how do I confirm this is the problem? If I unplug it does the light stay on or should it go out?

mr.unnatural

You've got a bad ABS control module. I've owned three B5 Passats (a '98 and two '99s) and the ABS modules are identical to the A4. They all had the same problem. There's a wire between the circuit card in the center of the module that connects to the outer edge of the module that is prone to breaking. It's a matter of opening up the module case and soldering a jumper across the broken connection. You'll have to scrape away some insulation to get to the solder connections. The module then needs to be sealed with RTV to prevent moisture from getting inside.

If you feel brave enough you can try this yourself. I've seen pictorials that step you through the repair process but I don't have the link to provide you. There are places you can send it to for repair for as little as $100, but it shouldn't cost you more than about $200 for a rebuild. A replacement module can easily run you $500 or more. I've sent two modules to places I found on ebay and they both did a great job with fast turnaround times.