Audi A6 C6 avant MMI not working

[flyby75]

Hello,

I had a big leak due to the dreaded washer pipes broken, and the left side was flooded withe a few cm of washer fluid.
Washer pipes have been replaced, and will take weeks to all dry out completely.
Problem I still have is that the MMI 2 G is still not working.
I have the Bose option, DVD Nav, BT phone module.
Initially completely dead, but now the Audi MMI system screen comes up for a few seconds and then goes black again.
-I checked all fuses, and they seem to be ok.
-got the amp out, and made an optical loop.
-tried reset.
- also got the BT phone ECU out from underneath the left passenger seat, which was very wet!
So looks like this is the problem.

But I took the BT ECU out and connected the optical cables in a loop too.
Unfortenately MMI is still not working.( only MMI Audi start up screen for a few seconds, then black screen)

Only thing I noticed is that the optical cable going to the BT ECU is flashing the red light, but the optical cable to the Bose amp in the left back is not showing the red light.
So I don't really know what to do/check now?

Can anybody help, or give me some advice please?

Thanks in advance!

Regards

[apole]

Hi,

I'm not an expert here but do have some experience with the fibre side of things, which is what the cable with the red light on is that you refer to. Fibre is a loop system so any break in that causes all devices in that loop to stop functioning.

So if any of the fibre cables in the AMP, NAV, CD Changer etc are not properly in or broken nothing will work.

Also I'm not sure if the above is true should any device loose power.

Finally, water and electricity do not mix so you need to throw that into the mix here, could be one or more units are now faulty as a result.

Are you in a position to get the codes read, that may help identify the device(s) in question.

If you could find a way to bridge out each device in turn (you'd need some kind of cable to do that) you could work on eliminating each in turn until you found the faulty one.

Hope this helps.

[flyby75]

Hi apole,

Thanks for the quick reply.

It's the optical cable going into the BT ECU which is where the red light is coming out.
So, I thought that in that case it would be logical that there would be a red light coming out of the optical cable for the amp too.

I forgot to meantion that, I brought the car to a Audi "specialist" who solved the leaking washer hoses, and also tried the VCDS test.
but he said that ot was completely dead, and so he couldn't find out which modules where broken within the MMI system.
That's why I am trying to find out one by one.

I openend the BT ECU, which was soaking wet and looks like that's gone for sure.
I thought that if you do a bridge loop by connecting the 2 optical cables together ,so that you bypass the BT ECU to see if the MMI comes back to life.
so far, no luck!

I hope someone can help me further, and otherwise I will have to bring it to the Audi dealer I guess.....

[neilos100]

It'll be the main radio controller unit that's died. Same happened to mine....though its a facelift one so all in one box now. Have a look on eBay. My symptoms were identical...came on for a few seconds then off.....all buttons by gear stick refused to light up. Changes the main unit and all back to normal after removing component protection.

Sent from my phone...

[gupsterg]

Hi :) ...

Sorry to hear of your woes :( ... there are plenty of people here to help :grouphug: from meddling owners to the real mechanics/technicians/Master Techs :) ...

These kinda files really helped me learn the tech language and setup...

First off google for SSP 286 this explains the MOST (fibre optical loop)... this car and modern have data networks within them like say a PC network...

Next grab the PDF's linked here Possible 'new' Owner - Page 3 (http://www.vwaudiforum.co.uk/forum/showthread.php?132903-Possible-new-Owner&p=719250#post719250)

Like Andy said you must look at all modules/dry the elec.connections/bridge them...

Like Neil said you maybe getting the issue due to the MMI rack in boot being wrecked by water...

Have you bridged all connections fibre optical connections on modules which have been water logged? ref page 7 pf SSP 326 top right... if you put Adobe reader in two page view and view 6 & 7 together...

Read this as well if you already have not Link:- Ross-Tech: VCDS Tour: Optical Bus Diagnostics (http://www.ross-tech.com/vcds/tour/optical-bus.html)

[flyby75]

Hi,

Thanks for the replies!
I will have a further look when I have some more time, and most of the car is dried out.
Thank's for the PDF's!
I have disconnected the amp( which didn't look bad inside) and the BT phone ECU (was covered in water) and bridged both of them.
unfortenately I still only get the Audi MMI start up screen for a few seconds.

As Neil said I will have a look at the radio controller next.
The Nav DVD module is powered and I can get the dvd in and out.
Also the cd changer in the clove box is operating normally.

Regards

[gupsterg]

As Neil said I will have a look at the radio controller next.

Located above the DVD drive in MMI rack...


The Nav DVD module is powered and I can get the dvd in and out.
Also the cd changer in the clove box is operating normally.

Besides the power like Andy mention the fibre optical loop is the data network...
At each point you are bridging the loop the red light is a tell tale sign that section of fibre optic cable is OK...

Some useful links for you...

Link:- Fitting locations (MMI) for Avant (http://elsaweb.spaghetticoder.org/doc/A.en-GB.A00.5A60.04/31690514/3)

Link:- MMI layout (http://elsaweb.spaghetticoder.org/doc/A.en-GB.A00.5A60.04/31690487/3)

Now if you ref the MMI layout, the fibre optic is linking the modules highlighted in the SSP, so when you view cable connection one side will be live with red light other not (you can see direction of data/light flow by arrow on the plug)...

[flyby75]

Thanks gupsterg,

Yes , that's what I thought too.
if there's no optical red light( data in) going into the amp there must be an optical breakage somewhere before.

- Someone any idea where that can be?

I have the car in the garage now to dry out completely.
I will buy a more professional optical bridge so I can leave the BT phone ECU out of the loop.
( I have connected the 2 optical wires needly together with tape:) to make the loop which isn't the best)

Regards

[gupsterg]

Read this as well if you already have not Link:- Ross-Tech: VCDS Tour: Optical Bus Diagnostics (http://www.ross-tech.com/vcds/tour/optical-bus.html)

In above link... post 5...



VW/Audi sells a handy loop of fiber (part number 4E0 973 802 ) that can be used in place of each of the components in the system.

I keep meaning to buy a few... if you get some... I will buy 1-2 from after you've used them... will be lot better then your current method...


( I have connected the 2 optical wires needly together with tapehttp://www.vwaudiforum.co.uk/forum/images/smilies/smile.png to make the loop which isn't the best)

You may have done this well but you really want the bridges :) ... you could be causing errors by this...

[flyby75]

Thanks for all the replies so far!
Unfortenately the Audi specialist couldn't read anything out with VCDC ,gupsterg, otherwise it would have been easy:).
I just got an email back from Audi that I can buy the loop bridge direct from the dealer in my town for £10.
So that' s what I am gonna do next when I have a few days off work.

- maybe someone can tell me this?: I did an own loop connecting the 2 optical cables together from the BT phone ECU under the front left seat and the was a red light on and off from the optical in.
I think the next in line is the amplifier and there was no red optical light from the ingoing cable.
(both PHone ECU and amp disconnected)
Does this perhaps mean there is no good loop connection with the optical in and out from the phone ecu so the optical light will never reach the amp?

I'll keep you posted, as I know this is a very common problem with the A6 Avant's......

[gupsterg]

Unfortenately the Audi specialist couldn't read anything out with VCDC

Did the specialist do MOST loop test (look at VCDS link) with bridges in place? or just an "Autoscan" for fault codes?

[flyby75]

He tried a VCDS link with no bridges in place, and all equipment still connected.
He told me that it was completely dead, even the diagnostic of the whole car....
But I am not sure how much of an Audi specialist he is on this subject;)

I have 2 loop bridges ordered with Audi, and they should come in tomorrow or so.
When I am back in the country in a few days, I can do some better testing!

[flyby75]

Hello,

Well I had time to have another look today:).

I bought 2 Audi optical loop connectors....

-I put an optical loop connector between the BT phone ECU...still not working.
-Next I put an other loop connector where the Bose amp was....MMI is working again :D
So unfortenately the Bose amp is broken, but at least I know this now.

I have someone looking at the amp to see if it can be fixed.
Otherwise I have to find a second hand one.
It' s a Bose 4F0 035 223 D.

Can anyone perhaps tell me if I can buy an amp with a different last letter, or does it have to be "D" model?
I know I have to get component protection off.

Hope someone has experience with this?

Thanks!

[gupsterg]

It' s a Bose 4F0 035 223 D

Below is list I can see where yours appears...

4F0 035 223 A

4F0 035 223 D

4F0 035 223 F

4F0 035 223 G

They each have a VIN range associated with them... but when selecting 4F0 035 223 D it supersedes to 4F0 035 223 G ...

You will need component protection removed when fitting the replacement AMP, regardless of new or used...

Link:- Audi VW Volkswagen Skoda Seat Independent Specialist London (http://www.audivwsc.co.uk/)

Above garage is forum sponsor, close to you, can remove CP & code for you, charge vs Audi 1/2 the price...
May also be able to advise on P/N compatibility... I'm only reading a screen as a meddling owner :Blush2:...

[flyby75]

Thanks for the quick reply!
I will contact him if mine is beyond repair...

[flyby75]

Hello,

I just wanted to thank everybody for the help.
It is all working again.
I bought an amp from ebay with end letter G.( had a 4F0035223 "D" before)
Build it in, and just had the component protection removed by Audi:).
nice to have some decent Bose sound again in the car!

[gupsterg]

http://www.youtube.com/watch?v=_MVonyVSQoM

"Luv it when a plan comes together"

[glitterfuzz]

I have the same issue with the A6 C6 Avant (2007) where water has leaked from the washer pipes onto the mmi unit. If I find a replacement radio unit, can I just swap it with the current one? Does anything need to be done to the car? Im struggling to find anyone who can help me with this!

[Jef trayfoot]

If the loop break doesn't work then try the loop break on more than one device. Other option is to disconnect all devices optic cables. I have 3 in the boot, one under carpet passenger side, CD changer and 2 behind glove box. Shine a torch down the cable and work your way round the loop. I did that to find a cable was damaged between the CD changer and bt module. I have the map written down at home so if you want more help then private message me.

[Mike2.0TQ]

Is there any way to safeguard against this happening?

Thanks

Mike.

[neilos100]

The day the music died (http://www.vwaudiforum.co.uk/forum/showthread.php/140159-The-day-the-music-died?highlight=day+music+died)
Have a quick look here.....same thing happened to me....it's not pretty but I opened up a plastic bottle and using the bolts for the mmi unit screwed it over so any water will be diverted by the plastic cover...I also glued the corner joint in the washer pipe so it won't open up again.
Neil

[Andrew8999]

I have an 2015 Audi A6 3.0T. Few weeks ago it was flooded with water on the floor now the left trunk lid brake light won’t work. Also, radio module has no power and Pcv regulator valve is not working. I’m think it’s all linked together but can’t figure out which wire or ground is bad.
Following codes are:
01516 - Terminal 30 Left - open circuit
02901 - left brake lamp/turn signal/ tail lamp bulb 2 - electrical fault

Can anyone tell me if it’s fuse or wire/ground that could be the culprit here?

Update: I found the radio module 7.5 amp fuse was blown and I replaced it and immediately blew again.

Thanks