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jdebartolomeo
11-29-2016, 09:35 AM
I've been getting code p0441 incorrect purge flow for about a year now along with a bunch of other codes that I have fixed and now I'm down to this last one. When I start the car I hear a kind of gurgling noise coming from the rear maybe vapor canister area. The noise lasts only for a few seconds and then it's fine and I don't feel any performance differences (maybe gas mileage).
I can hear my evap purge valve clicking consistently and my gas cap is new. The last time I filled my gas tank I heard a little psshhh noise when removing the cap, this is the first time I noticed that sound.
I've been reading a lot of different things about the evap system and I just can't come to a conclusion as to how each component works and what they do, such as the leak detection pump, canister, and series of valves (LDP mostly).
So, can somebody please explain this system to me and what the solution may be to fix it.

Thanks.


Joe.






1999 Audi a4 Quattro 2.8L Manuel AHA

Believer
11-29-2016, 09:47 AM
Do you have VCDS? When I was troubleshooting this code, I first used VCDS to look at the leak detection system to see if it was passing. Once I concluded I didn't have a leak in the system, I could solely focus on EVAP components.

The EVAP system is fairly simple:

- A line runs from the tank to the canister (located beneath spare tire well, under the car)
- A line runs from the canister, up the passenger side of the car and connects to the N80 valve (purge valve)
- There is a Y off the N80 valve; A line runs from one side of the Y, across the firewall then connects to a vacuum source on the drivers side and a line also runs from the Y to the turbo inlet pipe or intake.

Things that can cause an incorrect flow code are: clogged EVAP lines, leaks in the EVAP lines, a failing N80 valve, a clogged EVAP charcoal canister, failed check valves in the EVAP system. When I fixed mine, the canister had failed and clogged the lines with this white powdery substance. I blew all the EVAP lines out; tank to canister, canister to N80, N80 to vacuum on drivers side, and a bunch of gunk came out. After that my flow code went away after a ecu reset.

Since you can hear the N80 valve clicking, I would assume that is ok. Next I would check the canister beneath the spare tire well. All the lines to it are held in place by one time use clamps and they hoses can tend to be stuck on there good. Once you have it out, blow through it to ensure no powdery crap comes out and give it a tip to ensure there's nothing liquid in there from overfilling the gas tank. From there, move on to cleaning out all the EVAP lines with compressed air. Assuming your leak detection circuit is good, something in those steps should fix your issue. Hope this helps

jdebartolomeo
11-29-2016, 02:41 PM
I will check out the lines and canister like you suggested but I must ask, did you also have a gurgling or slurping noise? and from what i've read about a clogged canister you will have trouble fueling the car and starting it after fueling which i do not have. Did you have any of these symptoms?

Thanks.


Joe.

Believer
11-29-2016, 02:48 PM
The clogged cannister did not cause me those symptoms but a busted n80 valve did. I have heard the gurgling in the past. Have not heard it since my evap system was functioning but to be honest I have heard it on my previous a4 and didn't have any evap codes.

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jdebartolomeo
01-08-2017, 05:49 PM
Fixed it a few weeks ago. Tested the purge valve for vacuum and it couldn't hold. Got a new Bosch one for like $40 cleared the code and it's been good.

So even if the valve is getting enough power and making the clicking noise it may be faulty from the valve not being able to fully close.