P0299 - Turbo / Super Charger Underboost

[amaury89]

Hey so i just got this check engine light and this error message came up 'P0299 - Turbo / Super Charger Underboost' , i was read up on it and some people have stated it was the Diverter Valve.

Has anyone has this issue and resolve it?

[MikTip]

Generally its caused by a boost or vacuum leak....

[amaury89]

Generally its caused by a boost or vacuum leak....

sorry if i ask this but what is a boost? i know its a dum question and it should go under the other forum ' questions you thought were too dumb to ask '

if its a boost or vacuum leak problem, how i can i fix it?

[Furly]

sorry if i ask this but what is a boost? i know its a dum question and it should go under the other forum ' questions you thought were too dumb to ask '

if its a boost or vacuum leak problem, how i can i fix it?

boost leak is an air leak in the turbo system. so anything from a intake hose, to a vacuum line, to a check valve, can cause this code.
the things that commonly cause this is a N75 valve, a diverter valve, a boost/vacuum leak, or the turbo itself.
i am battling the same problem right now, already replaced turbo and diverter valve and code still exists.
proper diagnosis is the key. otherwise you will just throw money at parts.

[amaury89]

boost leak is an air leak in the turbo system. so anything from a intake hose, to a vacuum line, to a check valve, can cause this code.
the things that commonly cause this is a N75 valve, a diverter valve, a boost/vacuum leak, or the turbo itself.
i am battling the same problem right now, already replaced turbo and diverter valve and code still exists.
proper diagnosis is the key. otherwise you will just throw money at parts.

Thanks for the input

[Furly]

No problem. It's all about helping each other out.
Find a shop that can do boost and vacuum leak tests for you. Or buy a boost leak test kit online, if you have access to an air compressor.
That's a good place to start.

[Jzamilpa]

Same code triggered on mine as well. No boost leaks found, already tested. My mechanic says its either wastegate or turbo.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

[customa4]

Here's a good way to test if the wastegate is working properly. There's more info in this thread about tests you can perform regarding turbo issues. I mentioned my problem in post #27 and there's diagnostic info after that.

http://www.audizine.com/forum/showth...=1#post9016067

Did you take it for a spin? Another way to check the waste gate is to clamp off the boost signal line from the high pressure side of the turbo to the waste gate. You can clamp it on either side of the N75. Take it for a careful spin. If the waste gate is working properly you should develop full (uncontrolled) boost since the ECM will not be able to regulate the boost through the N75.

If you get full boost you have a controls issue. If you don't get any more boost then you have a waste gate issue.

[Audi body]

Your cat might be clogged. Happened to me. If your chipped I would pull out your DV

[MikTip]

Another thing to do is "data log" your car:

http://www.goapr.com/support/datalogging.php

It reveals whats actually going on and very specifically!

You will see actual boost and requested boost!

Also scan for DTC codes.