So I've been trying to fix a problem that from the reading I've been doing seems to be rather common with alot a people with c5 a6's.
Mine's an '01 quattro.

My biggest problem is that I've been unable to communicate with the ECU via OBD2 port.

A little background information and what i've done so far;

Issues began when I put it back on the road from having it sit for about 6 months. Shortly after driving it a few times, my radio quit working along with cruise, cigarette lighter, interior dome, ABS light blinking. I cured ABS/Cig lighter by changing fuses. Seemed obvious to me that the electrical system may have been effected by something, given all these circumstances.

I've checked all fuses (including in ECU box under hood).
I've unplugged ABS module in engine compartment and tried testing, to no avail.
ABS light is off (ABS light was on and blinking, Fuse change solved issue, and ABS works fine now).
Recently performed entire timing belt and water pump service. driving it for three months problem free.
CEL is on.
Cruise control doesn't work.
No Radio (ordered radio removal tools, plan to check fuse on back of head unit).
(Both the radio and cruise used to work.


I'm guessing its a ground issue, my plans are to test grounds on modules, as well as check for water around TCM and ICM as i've read that these are under the carpets, can get wet, and interfere with the K-line, which handles some of the things i've been having issues with. (correct me if i'm wrong)

Any expertise in these area's is very welcome, I plan on not quitting until I've found the problem.
Thanks in advance for any and all help and input.

 

Well no hits on this yet, So I'll add some more here, see if it helps any of you come to a conclusion.
Since my last post I ordered some radio removal tools, changed the fuse on the back of the radio, radio started right up.
Cruise control isn't working, won't even get power. Fly by wire throttle has some hiccups in it, isnt operating perfectly. OBD2 port won't allow me to communicate with computer.
I'm planning on accessing each module next, as I've been told they all are on the K-line, and if one is bad, they all can be affected.
Any Thoughts are welcome.
Thanks

 

What VagCom scanner are you using?