Check engine light on 05.5 3.2

[fasttommyv]

I have an 05.5 3.2 quattro. It has 63k miles on it and the other day my check engine light came on. The car runs fine and normal. I pulled the code and it came up as 16839. (EVAP Emission Contr.Sys.(Gross Leak) Leak Detected). Does anyone know what this code means or how I can try diagnose and fix it with out paying audi like a $1000 to do it? Is there any problem if I leave it unfixed as it at least doesnt sound like a big deal on the surface.

Thanks for your help,

Tom

[i3oricua]

Best I can tell is maybe an exhaust leak. Does your engine noticeably louder like that tapping noise we get from our engines, but louder than usual? I good way to really tell is accelerate near a wall with a window down on the side the wall is on or through a tunnel. The noise will be magnified then and you'll really be able to hear it. If it was a vacuum leak then it would throw a different code I believe and you would probably feel a decrease in performance because you would either shudder or you would not really feel the turbo accelerating the car. Hope this helps and I hope the problem is simple to diagnose. Also, sometimes Midas or places like that will do check engine lights for free and I'm sure Autozone or one of those car parts store can to and they may be able to give you a better answer.

[Forfour]

I would start by looking for any crispy plastic lines or vacuum lines that are rotted and torn.

[pakratt99]

Make sure your gas cap is on tightly, that cause this code about 90% of the time.....no I'm not joking.....

[fasttommyv]

Thanks for the help. The engine has made a slight tapping noise since I bought it. I havent noticed that it has gotten louder though. The CEL came on half way through a tank, and I have since filled up making sure the cap is tight. Could the cap be failing and causing a leak? Seems kind of odd for a cap to fail on such a new car... I guess another thing worth noting that whenever I fill up here in CA, the pump always shuts it self off after 3 or 4 seconds of pumping. So I have to really push the nozzle in and up and hold it there and I can fill it up with only 2 or 3 premature shutoffs.

[Sanjman]

don't mean to sound like an ass... but when you tighten it, do you let it at least click three times?

[fasttommyv]

don't mean to sound like an ass... but when you tighten it, do you let it at least click three times?

Normally no, I just go once or twice, I have never seen a need to do 3 clicks. That being said, I just went out redid it with 3 clicks and the light is still on. If it is gas cap related, and the problem is resolved, will the light dissapear immeaditley, or will i have to pull the battery cable to reset the computer?

Thanks again

Tom

[cstarky15]

i only click my cap once and haven't had a check engine light from it!

[Allan T]

You have to reset the computer with vagcom or taking the cable off the battery.