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PDK Issue: Discussion of a Mechatronic Valve Body Rebuild, etc.

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57K views 322 replies 25 participants last post by  CARSATION  
#1 · (Edited)
Trim:
GTS
Year:
2018
So, yesterday I got the dreaded "Fault Of The Engine Control Unit. Gearbox fault possible. No R-gear. Possible to drive on" warning on my 2018 Macan GTS that I just bought. It drives fine until it warms up, then it starts jerking, then begins skipping gear 4, then skipping gear 2 and 6, and finally the above light comes on and reverse doesn't work. There is a thread in here on this and other transmission problems: https://www.macanforum.com/threads/...possible-no-r-gear-drive-on-possible.115490/page-11?nested_view=1&sortby=oldest

But, I'd like to create a dedicated DIY for this problem as that thread is now 8 years old and over 500 posts. So, it takes a minute to read through it to glean the info to either do the repair yourself or point your indie in the right direction. From that thread, what you are going to experience if you roll your Macan into the dealer is a recommended $25,000 tranny replacement. If you roll into your typical indie repair shop, they're going to likely recommend a $5,000 new Mechatronic valve body, or some version of used or rebuilt Mechatronic in which the part cost is about $1,500, plus labor.

However, our resident tech expert, @VAGfan , describes in post #482 of the other thread a DIY repair that sounds relatively easy (especially if you have access to a lift) and inexpensive:

"The first troubleshooting step is to get the stored trouble-codes (DTCs) from the Transmission Control Computer (aka "TCU" or "Tiptronic Transmission Control Module"). PWIS and other Porsche capable scan-tools often list the TCU as a "Tiptronic", even though it is really a Dual-Clutch/DSG/PDK/S-Tronic transmission. The "Tiptronic" name is what Audi calls a conventional torque converter automatic transmission with electronic control and manual shifting features, and the scan-tools just used the wrong marketing name for it.

You could try pulling the Mechatronics out and just replacing the two "Circuit Boards", cheapest thing to try.
Audi B8/B8.5 S4 Quattro 3.0T Drivetrain DSG Transmission - 0B5398009F - Mechatronics Repair Kit 0B5398009F (0B5 398 009 F) (ecstuning.com)
Another forum member had issues only when the transmission warmed-up. It was fixed with new "circuit boards", which also contain the temperature sensor for the clutch fluid, and an RPM sensor.
There are many of these circuit board repair kits available on Ebay and Amazon. Some are much cheaper than the "real" VW/Audi kit, but they may work fine....

The next more expensive fix is to get a new or rebuilt Mechatronics unit (just the valve body part, not with a new TCU), and install the original TCU onto the new valve body. Then, no TCU programming is needed (to write the VIN into it (needed for the immobilizer).
But, you will need to run the full Mechatronics adaptations/calibration with your PIWIS.

Valve body (mechatronics) without electronic control unit, automatic transmission 0B5 (DL501) 0B5325025T 0B5325031N regenerated (maktrans.net) "


So, cheap & easy, right? @VAGfan, you have my attention.

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Hopefully, @VAGfan will visit us to lay some DIY knowledge on us. If not, you're stuck with me through this journey.
So, first step, let's figure out what parts I'm gonna need. @VAGfan gives us a link to the ECS Tuning "Mechatronics Repair Kit", which carries a $610 price tag (ouch). He also says there are circuit board repair kits on eBay and Amazon for much cheaper. So, I'm going to check those out (and will report back). Plus, as long as I've got the Mechatronics unit out of the tranny, it sounds like there's some sort of filter - might as well replace that. And of course, new PDK fluid. So, off to eBay and Amazon I go.
 
#308 ·
I removed my mechatronic last night, cleaned things up, refreshed the fluids and filters, and re-calibrated via PIWIS. Took me about 5hrs, and managed to get the mechatronics back in on the first try!

Upon inspection and cleaning, I did discover a small about of sediment/metal shavings on the shift fork magnets. It wasn’t necessarily excessive, but MAY have been enough to throw an implausible signal on distance sensors. I also tested resistance in all solenoids, and each one was within spec.

Last night’s test drives were successful. Hopefully things remain smooth and error free.
Thanks for the guidance!
 
#309 ·
2015
Macan Turbo 40k miles

Been following this thread for awhile. I own a small dealer in CT. We do alot of highline car. We have rebuilt many of these megatronics and right now have one that I am very perplexed on.

The car got the typical R not possible. Scanned with PWIS, code was P284100 Distance senor 4 signal implausable. Did a complete rebuild of unit using Borg Warner rebuild kit, we always replace the shift plate as well when we do these.

Calibrated car afterward, took it for drive and right away through the same exact code. The car is also making a scraping noise when it shifts to 3 and 5 as well as when it downshits to thise gears. Took the unit back out a few times trying various things but still throwing code.

Later sent out entire megatronic unit to Mlreng who we have used in past. He sent me a whole new unit except TCU. Installed that and same issue. Scraping noise in same gears and throwing same exact code.

In the workshop manual for this tranmission is states the code is related to BAD TCU. I have done a bunch of these never seen TCU fail but sent out our TCU to Mlreng which he cloned and sent back a new TCU. Calibrated and exact same thing.

Seeming there are tons of posts and articles about the DL501 I cannot find anything like this. It is is only thowing one code and we scanned with PWIS and Autel. Is it safe to say the whole transmission is bad?
 
#314 ·
Cleaning the clutch forks seems to have resolved my very similar “implausible signal” issue noted above. The layer of metal on my sensor was quite thin, but cleaning them has smoothed things out for me over the last week. No codes since

Highly recommend it be SOP whenever a mechatronic unit needs to come out
 
#320 · (Edited)
The scraping noise is probably the syncros in the gearbox, which will make noise if the shift fork does not move to the fully engaged (or fully disengaged) position. Just like on a manual transmission car, if you don't move the shift lever fully into gear, or fully into neutral, as you release the clutch. Grind!!

Another thought, have you checked the level of the gear-oil, in the gearbox section? Might be worth changing it, if the wrong type of oil was put in there, the syncros may not work properly.

If cleaning the magnets does not help, then perhaps the syncros are worn in the gearbox, which would require a full disassembly / rebuild of the transmission.
 
#322 · (Edited)
Why does your fluid look red? The usual fluids for the clutch/mechatronics section are amber in color.

Also, it could be a problem with the position sensor itself (rather than the magnets). The position sensor is part of the black plastic vertical board that is bolted to the TCU. I am not sure where you can buy a new one.

Also, I sent you a Private Message.