MMI3G No Sound

[fielding67]

Hi, I’ve read a few reports about similar issues on various forums, but can’t quite find comments for my situation. Hoping one of you out there can be of some help?

I’ll try and provide as much detail as possible.

I have a 2012 3.0 TDI S-Line A7, UK model with the steering wheel on the correct side .
171,000 mile workhorse.
Standard 3G MMI with 7” screen and touchpad.
No Bose or B&O
I was having an issue with a crackling centre speaker. Couldn’t see any visible signs of damage when I removed the speaker a few months back to check if it needed a replacement.
A couple of weeks ago all the speakers have died. Not a peep out of them.
All other functions appear unchanged. Screen pops out, displays all screens on all menus. Sat Nav, media, radio etc etc.
All illumination on centre console control pad functions correctly.
All buttons and options still work for all menus.
Volume knob ‘works’ in as much as the screen shows the graphic of the volume going up and down.
But no sound, static, interference, nothing at all out of the speakers.

I’ve removed and refitted all MMI related fuses to see if this might reset anything.
I’ve done the 3 button reset procedure a few times.
I’ve carried out a normal scan VCDS, with no errors on 5f. 7f doesn’t appear on the scan.
I then went into specific modules and tested 7f and it says can’t communicate with controller?
Unfortunately all the code reports are on my old laptop and the email doesn’t work for me to send the output to my Mac.

I’ve tried an optical test, but the interface is an older unit and won’t do the optical test from what I can see.

What seems odd though is that ALL the other functionality is unaffected. I can reset tyre pressures, check oil levels, use sat nav, pair my phone.
So the rest of the comms to the unit seem fine.

I’m assuming it must be something in the bowels of the head unit where the sound board sits?
I tried removing the multiplug and refitting yesterday. All speakers wiring in the plug appear ok and there are no bent pins on the head unit.

Refurb head unit I guess?

A question though, if I fitted an aftermarket fixed touchscreen, would this still need the head unit internal amp or would it do the job anyway?
I’m better with the mechanicals than the dark arts of media systems, so please feel free to dumb down any technical replies.

Photos of labelling on head unit and the speaker wiring attached

Thanks

Mark

 

[aj84]

Interesting - I sold my 2015 A6 to a friend of mine a number of years ago however he too had maybe a similar issue.
In his case, the rear door speaker was crackly and eventually all sound stopped. But he had other odd but related issues:
1. In some cases, the sound would just start working suddenly and carry on until maybe the next time the car was on or a couple of times of off/on.
2. Sometimes when there was no sound, the sub in the boot would still work
3. Other times the sub when it worked would carry on working...even after the trip finished and the doors were locked.

It was really odd and again no errors logged...I think there might have been one but once cleared, it never came back however the issue remained.

We ended up buying a second-hand MMI unit from an A7 (obviously changing the front because of the spoiler button etc) and reflashed it back to the A6 firmware.
Took a couple of goes but it fixed it and carried on working for 6 months. A month ago, it reappeared its ugly head again however the next startup, it fixed it has worked ever since.


What we don't know is had we flashed the original unit again, would that have fixed it?

So yes while a MMI replacement fixed the issue, it could reappear again.

Other things we tested was when the sound was dead:
1. navigation voice = fail
2. Bluetooth sound including phone = fail
3. CD + Radio = fail
4. Voice command button = fail
Volume wheel would from memory show sound was going up/down so it knew media was playing

We did check for water ingress but could not see any and certainly no corrosion - given how long it was not working before he got it repaired, there would have been obvious signs of water if this was the issue.

 

[fielding67]

Interesting - I sold my 2015 A6 to a friend of mine a number of years ago however he too had maybe a similar issue.
In his case, the rear door speaker was crackly and eventually all sound stopped. But he had other odd but related issues:
1. In some cases, the sound would just start working suddenly and carry on until maybe the next time the car was on or a couple of times of off/on.
2. Sometimes when there was no sound, the sub in the boot would still work
3. Other times the sub when it worked would carry on working...even after the trip finished and the doors were locked.

It was really odd and again no errors logged...I think there might have been one but once cleared, it never came back however the issue remained.

We ended up buying a second-hand MMI unit from an A7 (obviously changing the front because of the spoiler button etc) and reflashed it back to the A6 firmware.
Took a couple of goes but it fixed it and carried on working for 6 months. A month ago, it reappeared its ugly head again however the next startup, it fixed it has worked ever since.


What we don't know is had we flashed the original unit again, would that have fixed it?

So yes while a MMI replacement fixed the issue, it could reappear again.

Other things we tested was when the sound was dead:
1. navigation voice = fail
2. Bluetooth sound including phone = fail
3. CD + Radio = fail
4. Voice command button = fail
Volume wheel would from memory show sound was going up/down so it knew media was playing

We did check for water ingress but could not see any and certainly no corrosion - given how long it was not working before he got it repaired, there would have been obvious signs of water if this was the issue.

Thanks for the reply

I haven’t thought about reflashing the unit.
I’ll be honest I’ve only really used VCDS for diagnosing codes, retracting rear brakes for servicing and a few of the simple mods (needle sweep on start up etc - because I’m still 12 years old inside!)
I wouldn’t have a clue on how to attempt the flashing, but was aware that if I bought a replacement unit I’d have to tackle that.

I’m away on business for the next couple days - Bluetooth speaker in the drinks holder for now!

I’ll give it a go on Friday and see if it works.

M

 

[fielding67]

Thanks for the reply

I haven’t thought about reflashing the unit.
I’ll be honest I’ve only really used VCDS for diagnosing codes, retracting rear brakes for servicing and a few of the simple mods (needle sweep on start up etc - because I’m still 12 years old inside!)
I wouldn’t have a clue on how to attempt the flashing, but was aware that if I bought a replacement unit I’d have to tackle that.

I’m away on business for the next couple days - Bluetooth speaker in the drinks holder for now!

I’ll give it a go on Friday and see if it works.

M

Having looked into it, I realise my ignorance. VCDS can’t be used to ‘flash’ the head unit. I don’t want to shell out a load of cash for upgrades. I simply would like to reflash the existing firmware to see if it sorts things out. I use Waze and Spotify for Nav and Audio. Only using the radio on the head unit and the Bluetooth for calls.

Any ideas on how I can get my current setup on an SD card to re-flash it?

Another alternative… as the unit is fully functional in every other way - just no sound. Would there be a way of taking the sound output pre-amp (I understand it’s an integrated amp in the head unit) and pushing it through a fairly standard external amp and then use my current speaker set up.
I’m reluctant to buy a used head unit as there is the potential for CP override needed and as this problem seems to be a ‘known issue’ across other users, no guarantee it’s it going to go the same way in a short space of time.

Any advice welcome. Currently stuck with my Juiceblock speaker wedged between dash and windscreen for the moment.