EngineeringTruth

For the past 3 weeks, the MMI screen will about 2/3 of the time make one or two loud clicks as it opens up, towards the end of the screen being fully open. It is much less frequent on closing but it has happened . From close up it sounds like the the cogs in two meshing gears jumping as resistance is encountered. I also have seen the lower right corner of the screen vibrate as the clicks are made. I include a video recording of the issue.
If anyone has experienced this, please let me know what to do to fix this. I have read somewhere on this forum that MMI screens on the D3 were prone to having issues with the gears and that some enterprising tinkerer actually came up with a fix.
Does anyone know a way to have the screen stay up permanently either by way of VCDS (or similar products) or by taking out a fuse?
My D4 is a 2012 A8L with 37,000 miles.

MP4.2+6.0

Sounds like you are indeed experiencing the early signs of MMI screen gear failure. Pretty standard/common for D3's. where its closer to a "when, not if" scenario. Did mine on the 2006 W12 by about 8 years in IIRC. Symptoms leading up to it sounded more or less like you describe.

Haven't heard of a gear kit for D4, but might be out there or to be developed as cars age. On D3, there is no known VCDS mod for it I have ever heard of, nor a fuse pull. There is a wire cutting mod where you kill power to the screen lift/retract, but that is pretty hack butchery to me. With D3's now going on 13-14 years old and at 10% of their original selling price, I get why it happens with some owners there as they get driven into ground. But definite value subtract to me. If I ever found it on a more modern used D4 I would walk...and also wonder what else got hacked.

EngineeringTruth

I found a solution that permanently keeps the MMI screen in the open position. This youtube video, helped with instructions to remove the MMI screen assembly from the dash. Once removed I could see what the issue was.
A pinion gear rides up and down a stationary gear rack as the MMI screen opens and closes. The gear rack is cut out of plastic that makes up part of the MMI assembly unit. However the base of the gear rack has developed a small crack from what I reckon to be the repeated force exerted on it by the pinion gear as it rides up and down the rack. So now, as the pinion moves and nears the end of its travel on the rack, it opens the crack at the base of the pinion wider causing the pinion to loose traction because the rack has moved away from it when it should have been stationary; and because the pinion momentarily do not have anything preventing it from snapping back into its designed position, it does so and the pinion and gear meshes again, hence the repeated noise I had described in my original post.
My initial intention with the disassembly was to determine what was wrong and determine if it was something I could fix; or something that will require buying a new or used MMI screen unit.
On further examination though, I noticed there are three wire harnesses going into different parts of the MMI screen unit. One of the harnesses plugs into a connector next to the electric motor controlling the motion of the screen. I unplugged that connector to see what will happened. Power to the motor was cut off. However power to everything else remained. I tested the buttons on the dash that control the MMI. All worked as designed except for the one that controls opening and closing the screen which no longer does so. Only now it toggles the screen off and on, which I now realize is the secondary function of the button.
I carefully re-assembled the MMI screen unit, with the screen in open position. Then with OBD-Eleven I scanned for fault codes. I had several but I recognized that except for one code, all others were related to dissembling and re-assembling the dash. I cleared the fault codes, then re-scanned. Only one fault code remained and as expected it was the one related to disconnecting power to the MMI screen motor.
It has now been 3 weeks and about 700 miles since the fix. Other than the MMI screen now permanently in the up (open) position everything work as before the fix.
I looked on Ebay to see what a used MMI assembly could cost. The only complete unit I found was over $400. For a D3, the same thing is $100+. Since I intend to keep the car for at least another 3 years, I reckon when I'm ready to sell, there will be more used D4 MMI screen unit available for much less than $400. I could then buy one and swap with current unit or just disclose what I have done to the buyer.

LexusLSguy

Great video for a diy. Thanks for sharing.

MP4.2+6.0

Thanks for posting conclusion.

From your description, the issue sounds the same as the D3 A8's get as they get older. Pretty std. fix by about 100K and 10 years. On D3 there are some std. gear kits folks sell on eBay--three different gears in total; the one you describe sounds like the one that went on my D3, in the same way. One of the experienced D3 posters early on machined some gears in brass, and it took off from there. Sounds like that hasn't gotten to D4 yet though if you didn't find gear sets one eBay.

The wire one is also same as D3. On D3 it is a specific wire and folks typically cut it. For folks who can get their screen to the extended position before gears are trashed, some do it that way, albeit letting go of one of the A8 classic set ups. Easier on an older car to give up on something perhaps than a newer one.

Cirrusaudi

Great write up. A couple of questions:

1: Is the process same for a D4?
2: As the work is definitely above my pay grade, any Audiworld member in AZ willing to do this for me? I want to leave the screen up permanently.

Thank you.

boci

Those were the instructions for D4, OP stated that he owns 2012 A8L. The video also shows 2012 D4.

Cirrusaudi

Could someone tell me if this part will fir my 2018 A8? My MMI clicking noise is driving me bonkers.

https://www.ebay.com/itm/12362052057...=true#viTabs_0

Cirrusaudi

I finally decided to watch the Youtube video, maybe 10 times, and ordered an auto dash removal tool kit from Amazon for $10. The video makes it look too easy. The dash pieces are held by push in connectors that take more force than I was willing to try, so I took it to a local stereo shop. They charged me $49 to remove the dash front bezel, and unplug the power to the motor.

Now the screen stays up, like it should. Noises off! No problem.

But wait. Now I have a new problem. Because the analog clock had to be disconnected, now it is out of sync with the real time.


Question: Can someone Please tell me how to change the time on the analog clock?

Thank you!

EDITED TO ADD

The story has a happy ending. I set the clock source to satellite. About an hour later, the analog clock synced with the digital one. All is well in Audi World.

dgbaudiphile

You set it via the MMI. Go to Setup and then I believe Time is one of the four quadrant button options. Once you set it, the analog clock should also change.