Chrisb81

Hi all,I'm hoping someone can point me in the right direction,I have an audi a6 avant 2005,3.0tdi,the mmi system has completely stopped working,this has happened since I did some work to the rear brakes,while I was working on the car the battery went completely flat,since getting it running again the mmi will not switch on at all,no lights on the control panel,no screen,nothing. The navigation system and cd changer are getting power and I bought an optical loop wire to eliminate any faulty modules in the boot but still no change,checked all fuses,their is no damp at all around the components as I've heard this is a common problem,and I'm completely stuck as to why it would suddenly stop working!I've run a full VCDS scan on it which I will put on here as soon as I can. But all of the mmi system including control module are saying "cannot be reached",and a malfunction on the central electrics,I would appreciate any help and advice anyone can give as I've completely run out of ideas with this and can't really afford expensive garage bills lol,thanks in advance for anyone that can help

jonzie77

Sometimes I will get the "can't be reached" message and when I try again it works just fine. Two simple things to check depending on how long you've owned it, try holding down the power/volume **** a little longer and second the button over the glove compartment release turns off the display, it may have gotten pressed by accident. Also you mentioned the battery going flat, if you simply jump started it to get it running again then that is probably not enough. You should fully recharge it and if that doesn't work, replace it especially if it is the original battery that came in the car.

Chrisb81

Thanks for the reply,I have tried holding the buttons down but unfortunately their is no response,none of the buttons on the control panel will light up,as if their is no power getting to it,also forgot to say I have since put a new battery on as the old one was dead,was hoping this might have solved the problem but hasn't made any difference,is it possible I could of damaged one of the components such as the control module when I jump started the car?

beep-beep

A reasonable way is to find someone with VAG-COM and look up a faulty device in the loop. It could be blue-tooth module under the seat or the cd changer.
As a side note, to avoid running down your battery while changing rear brakes, I just leave the motor running while the caliper carrier is off (like 10 minutes each side).if you do it inside, you can buy a battery mintainer and connect to the outlet.

Chrisb81

Chrisb81

Wouldnt have a clue where to start with this lot haha

Chrisb81

So im guessing all of this points to the control head to be at fault,could this mean that the control head is not getting power and possibly a fuse or relay has blown? If so would anyone know the location of a fuse or relay that controls it? As I can't find any that seem to control that,or should I be looking into buying a used control head and see if it works? Thanks for the replies up to now its very helpful

jonzie77

I would say you're on the right track. Here is a snapshot of the fuses on the MMI control:

When you go to take the control out you may find something obvious wrong with it perhaps as simple as a spill. I have been operating with a junkyard control for several years now.

Chrisb81

Thanks for that,im going to take the control head out tomorrow and see if theirs anything obvious that's wrong,im guessing that if the control head goes bad it stops all the other mmi components working? Then I've got to get the component protection removed when I find a second hand part,turning out to be a nightmare this haha,great when their working though haha

jonzie77

When I replaced mine no component protection was indicated. I believe it's the units in the trunk that are most likely to need CP removed though, that being said, I replaced my Sirius module without the need for CP removal. I think what might be CP'd is the unit that the control talks to.