ekA6

I've had a problem with being unable to connect to any of the diagnostic systems on my 98 A6 for a long time now. I recently stopped by my local audi deal, where they tried to connect to the car with there tool and got nothing. The head technician said that he was positive that the problem was with the abs control unit and that it if one system fails it could keep the rest of the system from being accessed. I have now warning lights one inside the car and the abs seems to kick in when brakes are applied hard. Is this at all possible? Has anyone heard of this? Would a rebuild control module fix the problem?

Thanks

Uwe@Ross-Tech.com

If you can then accessthe other systems in the car, you've confirmed what the problem is.

Check for the presence of power (+12V) on Pin 16 of the diagnostic socket as well. No power there will cause "Interface not found" on all serial interfaces.

-Uwe-

ekA6

I disconnected the ABS control module and was still unable to connect to any system. There's 12V on Pin 16 with and without the ABS control module connected. Does this mean it is another control module?

Uwe@Ross-Tech.com

The next most likely culprit is the radio. A non-functional Concert or Symphony (due for example to a blown fuse) can keep the diagnostic bus (K-line) clamped low. IMO, this is a design defect in those radios. But it could be any control module on the bus, or even a wiring problem.

-Uwe-

ekA6

My radio seems to work fine and I have tried the diagnostic without it being connected which still gave me nothing. I get a buzz when I turn on the radio however. So if I repalced the Concert radio would the problem be possibly solved if indeed the radio was the problem? Otherwise would disconnecting each of the other control modules and testing the diagnostics allow me to determine the faulty control module?

Thanks,

Euft