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Backup sensor "brain" and MMI gear replacement questions.
Long story short, backup sensors are intermittently working. Took it to audi and they diagnosed it as backup sensor module/brain. They want $500 + labor for a replacement unit, but I'd rather find a used module and do the work myself. Anyone have a part number for the unit? I've googled and ebayed to no avail, as everything I find is about backup sensor replacement, not the module itself.
Second question, anyone used these gears to fix their mmi? At $20 it seems worth a shot.
http://www.ebay.com/itm/3pcs-New-Screen-Gears-Repair-Kit-For-Audi-A8-S8-MMI-Mechanism-New/201615438481?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20131003132420%26meid%3Dd51baaf91d1e45c38a1a5aa973bdd36b%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D161035186621
Side note, for a car with such low mileage - 48k - I'm sure having quite a few issues pop up with this thing.
I had the plastic gears replaced after they broke on mine, with the brass items.
Went straight in no hassles.
Getting the mmi screen apart was a little on fiddly side but doable.
Replacement gears
Re the PDC module, there are several revisions.
Revision C gives you the graphic on the mmi when the sensors are active.
The version in your car will have its full part number printed on it, including the letter on the end.
Not all problems are due to mileage, age is a factor as well. Intermittent backup sensor issues make me think fouled connections before a module. Not saying it couldn't be, but especially if you went to the dealer, they have a habit of replacing parts as opposed to diagnosing them, often resulting in unnecessary replacements. Do you know what trouble codes they got from a scan?
Not all problems are due to mileage, age is a factor as well. Intermittent backup sensor issues make me think fouled connections before a module. Not saying it couldn't be, but especially if you went to the dealer, they have a habit of replacing parts as opposed to diagnosing them, often resulting in unnecessary replacements. Do you know what trouble codes they got from a scan?
Second question, anyone used these gears to fix their mmi? At $20 it seems worth a shot.
Side note, for a car with such low mileage - 48k - I'm sure having quite a few issues pop up with this thing.
Did it myself. A good number of prior threads on this and how to's.
On something like gears, wear can variously be a prior idiot who thought it was a good idea (not) to put force on the mechanism for whatever reason, or more likely you bought a church lady car. Or soccer mom or retiree or... That is, 20,000 trips at 2.4 miles each is the same as 2,000 trips at 24 miles each mileage wise bur not wear wise. Wear wise it comes to total duty cycles on MMI gears (one up, one down per ignition cycle typically), and first example is 10x the other. Guess which one wears out gears faster on a per mile basis?
If truly a church lady car, some benefits but also some drawbacks. A lot of wear on seats can occur just sliding in and out for example--entries and exits (and seat time) arguably more important than miles. An in city car with short stops is worst. Think taxi or now Ubers for for harshest examples. Lots of cold starts and short driving distances not good. Oil can't burn off cold start water vapor and such, exhaust system struggles with water inside more, etc. Parking in a heated garage with ice/snow type conditions can accelerate rust and corrosion type issues on some parts. Maybe like parking sensors BTW. Obviously countervailing this a lot of things that do correlate much more with miles--brake and suspension wear, bearings, CV joints, etc.
You really should do a VCDS scan to find out what the specific issue with the parking system is. Could be a faulty sensor, wiring, or the controller.
As a side note, the 50k mile mark is where a lot of repair items start to crop up. Not just Audi, any car. Get through that and it's fairly plain sailing from then on with just bits and bobs as they come up.
If it's confirmed as controller failure (rare) then the replacement part number you want is 4E0919283C or later. Plenty on eBay for not much money. This will give you the option of the graphical parking display. The unit is located in the left side of the trunk and is an easy plug and play swap out.
For the MMI gears, if you don't fancy the hassle of gear replacement, another option is to simply disable the auto open/close feature and have the screen open all the time. See here: https://www.audiworld.com/forums/a8-...sable-2896700/
According to Audi, they checked the wiring, and swapped in a known working sensor, and still one of the sensors shows bad. Let me see if I can find the paperwork.
As swapping out with a good sensor didn't solve then almost certainly the module. There's usually plenty of them on eBay for less than $100, and it's a 10 min plug and play swap job. Just make sure you get rev. C (4E0919283C) or later to get graphical parking display. I did just this and it works great. Still have my old rev. B unit on the shelf in the garage.
08-02-2016, 10:32 PM
Backup sensor "brain" and MMI gear replacement questions.
