P0777 - 2013 DSG Sportwagen. Won't shift out of 1st

Car has shifted perfectly up until today. Had a horrible rain storm a few days ago, and went through some water. Car started to make some noise under the hood, seemed to time up with the engine RPMS, but that noise went away after I let the car sit for about 48 hours.

Now tonight, the car started bucking after slowing down to turn left. Once I pressed the accelerator the car hesitated and then surged into 2nd gear. An hour later, now the car refuses to shift into 2nd. Getting P0777 code.

Best case scenario/worst case scenario?

Well according to this video, which explains my cars symptoms perfectly, I need a new mechatronic unit. Looks like I'm getting rid of this vehicle. Can't afford to dump 2.5-4k into it.


https://www.youtube.com/watch?v=VethjiURXlg

So as an update to this, the day that I drove through the deep water and noticed the noise under the hood, the noise came from the right side (drivers side) near the radiator. I've been looking at mechatronic repair videos on youtube and I found it very interesting that this is the location of the mechatronic unit on my car. So, crossing my fingers that my insurance company accepts my claim. the car seemed to drive fine (noise was minimal/non existent after that initial day where I drove through the flood water) up until 9 days later where the car stopped shifting gears properly


Gonna call the VW dealership today and talk to a tech and get his opinion before I call Progressive

I would be checking for moisture inside the connector to the M-unit before I would condemn the whole thing. You went from step 1 to step 5 in a hurry.

oilhammer said:

I would be checking for moisture inside the connector to the M-unit before I would condemn the whole thing. You went from step 1 to step 5 in a hurry.

Click to expand...

Any tips? I have no idea what that is, or how to do that myself.

There is one electrical connector on the entire transmission. It is in the front right near the starter. It goes straight into the Mechatronics unit. Take the air cleaner out and it is right there. Twist it about a quarter turn and it comes right off.

oilhammer said:

There is one electrical connector on the entire transmission. It is in the front right near the starter. It goes straight into the Mechatronics unit. Take the air cleaner out and it is right there. Twist it about a quarter turn and it comes right off.

Click to expand...

you'll need to pull the airbox to get to it. If you look up Malone DSG tune directions, they'll show you exactly how to get to it.

Yes, "air cleaner" = "air box".

oilhammer said:

Yes, "air cleaner" = "air box".

Click to expand...

ah shoot my bad. I guess I wasn't paying enough attention to what you wrote. sorry about that.

figured I would post an update for anyone who was curious about the diagnosis


So I had a guy do the DSG service 2 months ago at 80k and apparently he didnt tighten the drain plug all the way. It managed to rattle itself lose and the VW tech at the dealership said the noise in the front end after going through the flood water was likely the plug vibrating while the car was running. It likely fell out either the day the car died, or the day before.



I can't believe the transmission wasn't completely dead. He said they just re-did the DSG service and the car is shifting fine. Fingers crossed. But knowing my luck with cars, something else catastrophic is coming down the pipe.


I still have the receipt for the shop that did the DSG service, think I have any shot of at least getting a refund? Guessing they're just gonna say they aren't at fault.

They were the last ones (before getting it fixed) to touch the drain plug... those things don't just decide to come out on their own provided they're tightened down enough.

Since you didn't first bring it back to the shop that did the service however, I'd assume they now have plausible deniability.