this post was submitted on 24 Jun 2025
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hmmm

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[–] [email protected] 13 points 3 days ago (12 children)
[–] [email protected] 3 points 3 days ago (1 children)
[–] [email protected] 2 points 3 days ago* (last edited 3 days ago) (2 children)

Does that give really detailed diagnostics? I’ve got a GTI that’s showing a P0299 underboost code that’s still around after swapping the turbo and I double checked everything and have no idea what to try next.

[–] [email protected] 5 points 3 days ago (2 children)

I have OBDeleven and have used VCDS a couple of times.

OBDeleven does give detailed diagnostics but any coding, testing or adaptations are locked behind a not so cheap subscription.

I honestly regret buying it, much rather pay a bit more for vcds and not have to do the subscription thing

[–] [email protected] 2 points 3 days ago (1 children)

Yeah the subscription sucks, but once the adaptions are done you don’t really need it.

Does VCDS have an app integration?

[–] [email protected] 3 points 3 days ago

One model works with phones, haven't tried that one though.

Yeah except the testing. I fixed the hvac and tried to do adaptations, had to pay for a full year subscription again.

I guess it depends on how much you mess around with your car.

[–] [email protected] 1 points 3 days ago (1 children)

I really just need to get more info than “low boost” so would I need a subscription?

[–] [email protected] 2 points 3 days ago (1 children)

Not for that, no. Reading codes from all modules and all live data monitoring are free. You should be fine without a subscription

[–] [email protected] 1 points 3 days ago
[–] [email protected] 1 points 3 days ago (1 children)

I’m not a GTI expert, but have you looked at the diverter valve? Or the charge pipes and connections? Either could be leaking boost, and I had a similar issue with my Mini years ago that turned out to be the diverter valve.

Good luck!

[–] [email protected] 3 points 3 days ago* (last edited 3 days ago) (1 children)

I replaced the diverter valve, same problem.

The charge pipe was disconnected at first after I replace the turbo - metal clip wasn’t locked - but still low boost after that was fixed.

Had my usual mechanic do a smoke test and no leaks.

And the turbo had a brand new boost control valve and diverter valve.

And the other weird thing is my old turbo seemed to be fine, with no play in the wastegate or friction.

[–] [email protected] 4 points 2 days ago (1 children)

lol is the boost pressure sensor bad?

It’s gotta be that or rings because it’s going somewhere. And it sounds like it’s all coming out of your wallet right now. 😅

[–] [email protected] 2 points 2 days ago* (last edited 2 days ago)

She’s my first project car and I guess she wanted to be a doozy.

Also if my rings were leaking 8-10 psi of boost you’d think it wouldn’t drive at all, let alone be about as good as a regular Golf

Maybe it needs a good nut blasting in the intakes

ETA: Also my coil packs gave out a while back and my mechanic did a compression test on it and everything was fine.

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