2011 Q5 2.0T with a P0299 Fault

[turmoil]

Had my Q5 in for the 95k service today everything went as expected, except I got a phone call saying the tech saw a fault for P0299 saying it's under boosting. I have never had an issue with this car and always adhered to proper ranges for maintenance. I was kinda shocked to see he found that particular code since I don't push this car hard at all. Never had a check engine light in the past month -- when the tech said the fault is from -- and never noticed an issue with performance.

Not sure how common this is, but curious how serious it is? They quoted me over $2300 to fix it. Not too eager to shell out for it at the moment since new tires, brakes, and rotors are looming

Just curious if other people have ran into a similar fault with their Q5. Thanks!

[SQive]

If you're not seeing/feeling any performance degradation, it's probably just a sensor.
If that is truly the case, they're really bending you over for $2,300.

[riceboy22]

Seriously, what are they saying they're going to do for that $2,300? I would imagine that fault could be the result of any number of things. Did they give you any explanation for that estimate or just pulled out a number?

[turmoil]

Here's what the note said on the inspection sheet:

"found fault P029900 Turbo/Supercharger under boost, turbo is starting to go out. Recommend replacing turbo charger"

The service rep didn't really have any other input for me. I really haven't noticed any performance degradation, so fingers crossed it's just a sensor. Out of curiosity, if the turbo were to fail, is that something catastrophic that could cause other damage or more of an isolated failure?

[A U D I]

The turbo being under boost can be from the wastegate failing by having play in rod its connected to. ALTHOUGH, this fault can be given for other reasons instead of the turbo. Yours being a 2011 could have a wastegate that from the factory was improperly made. On your motor you would not feel it during the initial failing time because the boost pressures. They should be able to confirm if the turbo is the problem for sure and be able to show you why. That said, there can be other things that give you that code besides the turbo.

[riceboy22]

Here's what the note said on the inspection sheet:

"found fault P029900 Turbo/Supercharger under boost, turbo is starting to go out. Recommend replacing turbo charger"

The service rep didn't really have any other input for me. I really haven't noticed any performance degradation, so fingers crossed it's just a sensor. Out of curiosity, if the turbo were to fail, is that something catastrophic that could cause other damage or more of an isolated failure?

The turbo failing could be potentially catastrophic but isn't guaranteed to be. It really depends on the type of failure and then what happens afterwards. I know plenty of guys with the 2.7T motor back in the day who blew turbos and simply upgraded to K04s. I'd want to know like @A U D I said how they actually diagnosed that it's the turbo.

[turmoil]

I'd want to know like @A U D I said how they actually diagnosed that it's the turbo.

I'll have to inquire again. All I was told from the service rep is what was on the sheet.

What other potential parts or areas could cause this fault to be raised (assuming it's not the turbo itself)?

[riceboy22]

I'll have to inquire again. All I was told from the service rep is what was on the sheet.

What other potential parts or areas could cause this fault to be raised (assuming it's not the turbo itself)?

Besides the turbo itself it could be the boost pressure sensor like @SQive mentioned, a leak (or restriction) somewhere along the intake path, or a faulty wastegate like @A U D I mentioned. Let us know what they say about how they diagnosed it was the turbo and eliminated the other possible causes.

[turmoil]

Besides the turbo itself it could be the boost pressure sensor like @SQive mentioned, a leak (or restriction) somewhere along the intake path, or a faulty wastegate like @A U D I mentioned. Let us know what they say about how they diagnosed it was the turbo and eliminated the other possible causes.

Thanks for the info I appreciate it! I probably won't be headed back for a little bit but i'll bump this thread when I find out.