Check Engine P2279 Intake Air System Leak-?

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Have searched for reason for this code. Replaced EVAP cannister, purge valve, gas cap, oil cap, MAS, Cleaned throttle body, and replaced Valve Cover. (pending codes-P2279 Air intake system leak. P0171 System too lean bank 1 & P0507 Idle control system higher than expected. I cleaned throttle body. replaced oil fill cap, gas cap, Coils, etc... Last year I replaced Valve cover (bad PCV ) and code went away until I tightened a screw and broke it. Recently replaced valve cover again and down to P2279 only I think I may not have cleaned the breather hose or other things properly at the time and tripped the P2279 code again? How can I check to see IF that was the problem- other than replacing again and making sure I clean out attached hoses correctly? What ever the cause of P2279 the Jetta has amazing response/performance. I don't feel anything wrong while driving it? Used propane,water & carb cleaner, to find vacuum but came up empty? Any advice or opinions would be appreciated.

toni-bridge006b92e8 in Las Vegas NV

Jul 31, 2017

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Popular Answer

casey40510on Aug 3, 2017

Hello, Check your egr system. If the EGR valve is not closing properly, you will have a small vacuum leak all the time. Also, the EVAP system should not be the concern because you would have EVAP leak detection pump noises and EVAP codes. The idle air control valve could be leaking as well, and don't forget to spray the fuel injectors and intake manifold gasket while looking for leaks. Which engine do you have? Which transmission?

toni-bridge006b92e8on Aug 4, 2017

It is a 2005 VW Jetta, 2.5L, 5Cyl, Autostick - I tend to lean toward the valve cover replacement being the issue because I had the same code at smog last year and failed. I fixed the valve cover (because it is one piece with the PCV) and it solved the problem (2279 code) and passed smog. Then I broke one of the cover screws and the code came back. I was careless when I replaced the valve cover a second time and did not wipe out the breather hose connection - I later saw the warning right on the box that I needed to do that or it was likely to throw a code on me again - Guess what? They are right. Arg! So now I don't know if I should replace breather hose or the whole valve cover again?

casey40510on Aug 4, 2017

The breather hose on the 2.5 suffers from oil buildup, right? Is there a check valve in the breather hose?

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