Rumble/Vibration at around 1200 to 1400 RPM after TDI Fix

First time poster but long-time reader. Great forum!

I got my MK7 Golf TDI (auto DSG) into the settlement fix about two months ago in Toronto. At the time, I hadn't even done the Phase 1 fix yet, so they did the entire fix (phase 1 and 2) simultaneously. Ever since then, I've noticed a very discernible rumble at low RPM in pretty much every gear, but most noticeably from 1 thru 4. If I'm coasting with foot off the pedal it won't happen, and will only trigger when I'm accelerating through that RPM range. Also, I'll only be down in that RPM range if driving very light. If driving more spirited, then it will usually up shift above that RPM range or at least accelerate through it quickly where it is not as noticeable.

It feels like it's coming from the engine bay, but that could just be vibration transmission. It can be felt most through the steering wheel and the seat (which is kind of obvious because those are the points of contact with the car interior). I've searched online and this seems to be a common behavior for TDIs, but I never experienced it to this degree until after the TDI fix. Perhaps the reprogramming changed the shift points to up shift faster and thus stay in a lower RPM?

I brought it back to the dealer that did the fix, and they told me it was 'normal', although in all honesty they never spent long enough with the car to really diagnose the issue (they spent longer on an alignment issue that also popped up after the fix).

Just curious if others have experienced this as well post fix? I can live with some rumble, but this is to the point where it is unpleasant to drive. And it definitely was not like this before the fix.

Thanks in advance for any inpput/advice!

is it more obvious in the higher gears low rpms under load, like when it just upshifts?

It's noticeable from 1 to 2, 2 to 3, and 3 to 4. And yes, it's right after it up shifts when the RPM drops. In the higher gears the RPM starts off a little higher and it isn't as discernible.

Sounds like engine lugging. Or does it sound different than that?

D-Cup said:

Sounds like engine lugging. Or does it sound different than that?

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Correct me if I'm wrong, but isn't engine lugging when you're throttling hard at low RPM because the gear is too high? I thought that would apply more to manual transmission.

I don't think that would be my case since it's an automatic transmission, and I'm definitely not throttling hard. As I mentioned in the OP, it's actually most noticeable when I'm very light on the throttle after an upshift.

in a DSG in D, the engine will never lug. In our phase 1 '15 Passat the one thing the DSG loves to do is down shift once asked for more load.

Just because it’s “auto” or “DSG” doesn’t mean that engine lugging doesn’t happen.
It happens in manuals, yes - when a person mismanages shifting.
It can also happen when a computer “mismanages” shifting.
Every TDI I’ve driven exhibits your symptoms below 1400rpm. ALH, BEW, BRM, CJAA.
If it always goes away once you get above ~16-1800rpm, then that’s what it sounds like like.
It sounds like your fixed computer is programmed to prioritize lower emissions via lower RPMs over engine performance.
You can “manually” shift your DSG if you like, keep it in the higher RPM range, and see if you can eliminate the symptoms.
Some other members on here have improved their mpgs and driving fun post fix by doing so.
Or, you can look for some other solution. I’m not a professional or a guru, so everything I say is worth exactly what you paid for it.
Either way, I wish you happy driving. Cheers.

Is the diesel fix known to lower RPM bands at shift points? As I said in the OP, I definitely did not notice this level of vibration/rumble before the fix, but I also wasn't as aware of the RPM at shift points previously as well.

I suppose I could just change my driving habit to be harder on the throttle and not "babying" it as much. Not sure if that would be better for gas mileage or the engine in the long term? I always thought diesels performed best (in terms of power efficiency) at lowest RPM and highest gear.

Use the search feature to find “post fix impressions” and you will be shown a few different threads on the topic. Enjoy the reading - there are more people with DSGs that experience loss of power, mileage, both, or neither. Depends on the individual vehicle. Remember, these cars were all in varying degrees of condition going into the fix, and all went to varying environments/driving demands post fix - so different people have different experiences. If you read enough of these threads you’ll get a better idea of what’s going on with your car, whether or not you want to do anything about it, and, if so, what and how to do that. Enjoy the reading.

EDIT:
I have a manual, however, pre-fix, I enjoyed a level of performance from 1600-2200rpm.
Now, to enjoy that same performance, I have to stay/shift to keep 2000-2800rpm.
If I don’t, it sucks, but my mpgs are less bad. I drive to be happy, so 2000-2800rpm it is, and I get 33-34. Last tank was 35mpg - all highway.

Besides all that. Do they loosen / remove Exhaust when doing Phase 2 a ?

They remove the subframe to do the fix. Tell them to make sure everything is torqued to spec, attached properly, and the alignment is correct. Bring it to a different dealer if you want (I would).