Hi all. I just wanted to post my experience with the fault code P2404. Right to the solution in my case was a vacuum hose leak.
Now for the long answer. i have a 2008 audi a4 ive owned since i purchased new. My sister has had it for about 2-3 years though. Anyways she moved to Florida and i moved to Washington and just had the car shipped my way. Before she sent it off we had Audi in Pensacola Fl did a diagnostic. according to them it needed a serp belt tensioner and an issue with the evap leak detection pump. They wanted $1600 for both. had it shipped and started working on it myself. As i was googling i found a ton of results as to what it might be. The tensioner was fixed for about $30 and 10 min time. The evap was harder to figure out. N80 valve was the most popular result it seamed. I bought one from oreilly for like $20-30 but didnt put it in. I think i read something like if it failed it would have been from something else. Seen a test somewhere that said to take it off and blow through it. I just decided it was fine and looked for other problems. My old mechanic who is a wizard told me over the phone to check for vacuum leaks. Specifically to the brake booster. After 2 minutes looking around i found a small vacuum line to the break booster and also running through the top of the firewall. The boot going into the intake manifold was ripped about 1/2 way around and it has a little line coming out the bottom. Looks like someone in the passed j-b welded it together. I guess at some point someone fixed an issue in that way. $100 for a new hose from advanced auto parts and a code delete. Havent had an issue since. I just got a vcds sccan tool and tested the system. All is good. I hope someone sees this and may find it helpful.

 

This piece right here, I cant seem to find. I order this part, but it doesnt seem to be exactly the same.





This plastic part on the bottom is broken.

Any advice finding the correct part or other fix?

Thanks