Originally Posted by EngineeringTruth

I found a solution that permanently keeps the MMI screen in the open position. This youtube video, https://www.youtube.com/watch?v=HK0hpSDa0Dw 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.

Originally Posted by Audi Jesse

Hello,
I know this thread is old but did you drive assist or engine level stopped working after this?
Did your vehicle read the accurate oil level after disconnecting that plug? Thanks!

Originally Posted by EngineeringTruth

Things worked and still work over 6 years later as described in my solution. The harness I disconnected only supplies power to the electric motor that drives the screen. It does not affect any other component.

Originally Posted by Audi Jesse

Thanks for confirming, the only reason I asked its because after I disconnected that plug my screen stays up, everything since to be working fine except my drive assist. When I go to the drive assist it saids future not available…I also noticed that my sensors stopped working and rear camera no longer works.
Maybe is a sensor issue. Also the plug I unplugged is the one that connects to that motor I believe there where 3 or 4 different cables on that plug?

Originally Posted by EngineeringTruth

What Year, Make and Model is you Audi?