TimU

+1
Seriously old96A4, check your fuses.
I found the quickest way to test was to use a multimeter with a continuity "buzz" and touch the probes to each of the exposed fuse terminals.
Just go back and forth along each fuse block and test every single one.

24wheeler

There are a few hidden fuses. From memory there is at least one, possibly two fuse boxes under the hood. One to the side of the dashboard. There are also some unlisted ones below the dash. On mine there are a few fuses behind the steering wheel lower knee cover. Quite a few are not listed in my driver's handbook.

old96A4

Ok, I'll look when it's light out, so far all the fuses I checked were ok, in the normal places. rear and both sides of the dash.. I haven't look in teh book yet. for the most part they don;t tell you anything anyway. I'm sure I'll need to get a shop manual.

24wheeler

Be sure to use a simple test lamp or, as previously suggested, a multimeter for a quick and easy test of fuse integrity.

oaktreelimb

Address 07: Control Head
Cannot be reached


Try to fix this problem first.

TimU

Agreed, a visual check is next-to-useless.

old96A4, Do you have any other after-market components attached to the MOST loop, like an iPod interface or anything?
Or maybe something that's tapped into one of the component's power sources?

If all the fuses check out, start looking around at how to build/buy a MOST loop bypass cable.
Use it to start bypassing components to try and isolate them from the loop.

I know it's easy to say in words, but I know this would be a bit of a PITA to actually do in real life.

If at the end of that the only thing left is the MMI controls, see if you can find another Q7 owner in your area that will lend you theirs as a test.
A long shot, I know, but better than forking out for a new board, or killing your good one with a solder reflow attempt!!

See this thread (read all the way to the end) for part numbers, pricing and pictures.

Tim

old96A4

what is the control head, something for the MMI system or the Q7 itself??
not sure where to look, I'll have to find some docs and see where all this stuff is.. thanks fo rthe part numbers and picture etc... I'm not sure the control board with the ***** is where the problem is, we never spilled anything on it, just went out.. all of it at once. screen comes one for a few seconds but that's it.

TimU

I'm not sure *exactly* what the control head is sorry mate, so I won't comment and potentially steer you down the wrong path... having said that, *none* of the components on the MOST loop are contactable, so the Control Head is probably not the culprit.

I also stumbled across this link on building/buying a MOST Loop bypass cable, aka a "MOST bridge adapter" or "MOST loopback connector".
http://a6retrofit.tripod.com/article...ostbridge.html

Hope this helps.
Tim

TimU

BTW, I just had a good read of your VCDS log, and while I'm no expert, you might want to start with this component:
-------------------------------
Address 0F: Digital Radio
Cannot be reached
<snip>
1 Fault Found:
00384 - Optical Databus
011 - Open Circuit
Fault Frequency: 1
Reset counter: 104
<snip>
Date: 2011.10.28
Time: 07:49:08
-------------------------------

I think there were only two active faults at the time you scanned. This one and:
-------------------------------
Address 6F: Centr. Conv. II
<snip>
1 Fault Found:
01516 - Terminal 30; Left
012 - Electrical Fault in Circuit - Intermittent
Fault Frequency: 1
Reset counter: 147
<snip>
Date: 2011.10.28
Time: 17:48:45
-------------------------------

The Digital Radio fault occurred first, but the Intermittent Centr. Conv. II Electrical Fault has occurred more.

Another thing you could try (after you make sure you have an original copy of your current, broken VCDS log), is reset all the old DTC codes and scan again.

Please post the FULL log, not just the errors.

old96A4

I think the original full log might be to big for the forum, I'll do that when I get the VAG back and do a reset and reread. thereis another test in teh VAG that I can do to find the break in the loop. I bought on of those loop back things from teh dealer to use to take out the components one at a time to help debug which one is bad. The VAG found other issues with teh door locking handles and the rear tail gate sensor. I just have to get a shop manual to fnd out where all this stuff is. Any recommendations on which shop manual to get?? I post the VAG log when I get another one.