# Leak in Air Intake System P2279 - What to check



## dbk (Dec 29, 2018)

Hi friends!

I just got back from a year-long trip. The Audi has been parked outside. Battery died, and I had a hard time getting it to start (old fuel maybe?).

Once the car started, the engine struggled quite a bit. It shook. Seemed like there was some misfiring going on. 
But once the car warmed up, all was well. I fueled up with new gas and have been driving no problem.

I checked VCDS. 
There were some fault codes....mostly associated with the low-voltage of a dying battery.
A few faults regarding cylinder misfire and the engine running too lean.
I cleared them and they've never returned.

But now I'm stuck.

One fault remains. It won't go away. I clear the codes and then....it's back. So I'm thinking there is an actual issue somewhere.

Can anyone please advise me what I need to check?

NOTE: (Date is incorrect in the report, because I didn't adjust the onboard clock. The date should say 2021.02.11)
Fault Found:
008825 - Leak in Air Intake System 
P2279 - 002 - 
Freeze Frame:
Fault Status: 01100010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 94578 km
Time Indication: 0
Date: 2021.02.01
Time: 21:04:57

Freeze Frame:
RPM: 760 /min
Load: 14.9 %
Speed: 0.0 km/h
Temperature: 71.0°C
Temperature: 31.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 14.224 V

Readiness: 0110 0101


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## SwissJetPilot (Apr 27, 2014)

For a help with fault codes, you can run a Google search; "Ross Tech XXXXX" where XXXXX is the fault code. This will provide you with a list of possible symptoms, causes and solutions -

http://wiki.ross-tech.com/wiki/index.ph ... 279/008825


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## dbk (Dec 29, 2018)

Thank you!

I read through that before posting. And my best guess is that it's a PCV issue. Watched some Youtube videos and saw that PCV can cause this code as well as idle problems and 'engine running lean' code

Before replacing the PCV, I'd like to check the following...

Check Intake System for Leaks
Check Intake Manifold Runner

But can you tell me how that's done? I'm not even sure I know what the intake system is, let alone how to check it for leaks.

Thanks!

P.S. The fix you recommended for the convertible servo motors is still holding strong. Thank you again for that.


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## SwissJetPilot (Apr 27, 2014)

Glad the top's still working okay! [smiley=thumbsup.gif]

In case I missed it, apologies in advance for asking again. This will help so everyone knows what you have under the hood -

• Year:
• Engine type: (e.g. 2.0 TFSI - EA888)

You might want to try the Forum Search function for 'P2279' and see what comes up like these two for starters -

*BWA 2.0 TFSI PCV Valve K - R Differences*
https://www.ttforum.co.uk/forum/viewtop ... &t=1969643

*HELP!! PCV VALVE??*
https://www.ttforum.co.uk/forum/viewtop ... &t=1860093

If you're not that familiar with the engine operating systems, you may want to read through the engine Self Study Program for your engine. And you can also download the specific workshop manual for your engine so you'll have a better idea of how to check for problems and make the repairs -

*FAQ - Audi TT (8J) Workshop Manuals & Self Study Programs*
https://www.ttforum.co.uk/forum/viewtop ... &t=1833829

.


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## dbk (Dec 29, 2018)

Relies to your questions below. I'll read through the materials in the meantime.
Thank you!!

• Year: 2008
• Engine type: 2.0 TFSI


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## chrisj82 (Jun 15, 2012)

i remember when my pvc went bad engine didn't run well and would cut out when coming to a stop, put new pvc on and problem is gone.


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## SwissJetPilot (Apr 27, 2014)

*P2279 Intake Air System Leak - *

_Trouble code P2279 indicates that an air leak has occurred on the "metered" side of the Intake Manifold. When the Mass Air Flow (MAF), the Intake Air temperature and Oxygen Sensor show a disparity, a leak is recognized and the (fault) code P2279 is set. Air leaks at the Air Filter or hoses leading up to the MAF or Throttle Body are of no concern.

• The leak is present between the MAF sensor or Throttle Body and the Manifold._

Source: https://www.obd-codes.com/p2279

*What the P2279 code means - *

_P2279 is an OBD-II generic code for the Engine Control Module (ECM) detecting a vacuum leak into the engine. This means that unmetered air is entering the engine without the engine sensing it going through the Mass Air Flow sensor and Throttle Body._

*What causes the P2279 code? -*
_
• The Engine Control Module (ECM) calculates the amount of air going into the engine through the Positive Crankcase Ventilation (PCV) system. If the amount of air is more than expected then the Check Engine Light will come on and (fault) code P2279 is set.

• The ECM learns the throttle opening angle and stores it in memory. If the Throttle Body is cleaned or adjusted without the throttle relearn process performed (Adaptation), then a (fault) code may be set.

• The PCV valve or hose is leaking or cracked causing excess air to get into the engine unmetered._

Source: https://www.yourmechanic.com/article/p2 ... ay-safford

*How to Replace PCV Valve on Audi TT Mk2 2.0 TFSI*





*Note* - While this video describes the parts and procedure for replacing the factory PCV valve, there are PCV diaphragm replacement kits which are a bit less expensive. Check companies like *RKX-Tech* for price and availability.


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## dbk (Dec 29, 2018)

Thanks for all the intel  I pulled off the PCV today to get the part number from the bottom. Ordered a new one.

Of course, one of the clips on the hose just had to break off. [smiley=bomb.gif]

What do you think? Zip tie time? Or new hose time?


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## SwissJetPilot (Apr 27, 2014)




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## dbk (Dec 29, 2018)

A little update here: I installed a new PCV valve and cleared the engine error codes. No engine light for a few days. But then it came back on with a different error. Now it says "Too Lean at Idle"

Before, it would specifically state "Leak in Air Intake System" and as soon as I'd clear the code in VCDS, it would pop back on. 
Now, when I clear the "Too Lean at Idle" code, it takes about a day to come back. The "Leak in Air Intake System" code has yet to resurface.

When swapping the PCV, I noticed some hoses were cracked (pictures), but researching part numbers, they point to the brake system. Am I correct? I put some tape over the cracked parts and some zip ties over the tape to keep the tape in place.
Could these cracked hoses be giving the problem or is there something else to check?

Thanks for all the help.

BTW: car drives and idles great. No shake or lag whatsoever.


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## TT'sRevenge (Feb 28, 2021)

dbk said:


> When swapping the PCV, I noticed some hoses were cracked (pictures), but researching part numbers, they point to the brake system. Am I correct? I put some tape over the cracked parts and some zip ties over the tape to keep the tape in place.
> Could these cracked hoses be giving the problem or is there something else to check?


Yep that's your vacuum leak right there  Need to replace those hoses that are cracked. Tape and zip ties may work in the short term but the best idea is to replace them. If that's a brake vacuum hose, if you lose vacuum to the booster there goes your power assist for your brakes  So you def. want to replace them ASAP for safety!

This is a turbocharged engine and I believe the brake vacuum is supplied by a vacuum pump but what I think that gizmo there might be (the plastic thing) is a check valve so that when the engine is in vacuum it's possibly supplied by the engine vacuum, under boost the pump gives it vacuum...not 100% sure on that but providing it's pulling from engine vacuum at some point--that's going to be exactly where you are leaking from.

I believe if you fix that your issue will be solved.


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## dbk (Dec 29, 2018)

Thanks for that great advice TT'sRevenge! Does anyone know if I can use rubber tube or fuel line with the right diameter, rather than getting the OEM hoses? They seem overpriced for what they are, and some options on eBay even look like lengths of rubber tubing with metal screw clamps.


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## TT'sRevenge (Feb 28, 2021)

dbk said:


> Thanks for that great advice TT'sRevenge! Does anyone know if I can use rubber tube or fuel line with the right diameter, rather than getting the OEM hoses? They seem overpriced for what they are, and some options on eBay even look like lengths of rubber tubing with metal screw clamps.


Any type hose that has the same inner diameter and doesn't collapse under vacuum would be appropriate. I think fuel like would definitely work. Only things to be careful of would be if there are bends involved which kink the hose--the factory hoses are probably shaped so they avoid things like this; the other thing would be the metal clamps--don't overtighten those over plastic fittings/connections as you can end up breaking the plastic.


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## dbk (Dec 29, 2018)

Awesome! Thanks.


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