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I finally resolved my P2404 code. Pictured is a portion of a small plastic tube that runs from the intake manifold down toward the dipstick and connects to a rubber hose on the left side of the engine. When I went to remove the tube it cracked off easily. So I am assuming that the crack created a vacuum leak that tripped the code. So happy. Hope this helps someone else in the future.
I finally resolved my P2404 code. Pictured is a portion of a small plastic tube that runs from the intake manifold down toward the dipstick and connects to a rubber hose on the left side of the engine. When I went to remove the tube it cracked off easily. So I am assuming that the crack created a vacuum leak that tripped the code. So happy. Hope this helps someone else in the future.
Do you happen to know the OE part # for this tube? We did a smoke test and no leaks from this tube, but will re-inspect. Seems like a very brittle piece that should be replaced anyways over time.
I just found and fixed a problem with this tube. What was interesting was that the tube was apparently intact - you could wiggle it and see that it wasn't broken. I was looking at it again in bright sunlight, ready to do a vacuum test, when I could see a crack in the elbow near the dipstick - just barely visible. When I flexed the tube while looking at the bend, I could see that it was surely cracked. When I went to remove it, the tube just shattered - the heat had taken its toll over the past 10 years. I went to AutoZone but no metric sized vacuum hose - but 3/16" worked like a charm so I just connected the two ends any my CEL problems were over!
EDIT: well, not over but mostly gone. A week later P2404 showed up again. I changed the J757 relay which is located as the center relay in the sealed compartment on the drivers side, next to the brake fluid canister (part no 4H0-951-253, from genuineaudiparts.com) and it stayed off for another few days now its back on). :-(
I just found and fixed a problem with this tube. What was interesting was that the tube was apparently intact - you could wiggle it and see that it wasn't broken. I was looking at it again in bright sunlight, ready to do a vacuum test, when I could see a crack in the elbow near the dipstick - just barely visible. When I flexed the tube while looking at the bend, I could see that it was surely cracked. When I went to remove it, the tube just shattered - the heat had taken its toll over the past 10 years. I went to AutoZone but no metric sized vacuum hose - but 3/16" worked like a charm so I just connected the two ends any my CEL problems were over!
EDIT: well, not over but mostly gone. A week later P2404 showed up again. I changed the J757 relay which is located as the center relay in the sealed compartment on the drivers side, next to the brake fluid canister (part no 4H0-951-253, from genuineaudiparts.com) and it stayed off for another few days now its back on). :-(
Sorry to hear that. milan_o(Tony) and I have had the same lingering problem. I am convinced its an electrical issue. Possibly corrosion underneath the relay box leading to that J757 relay. If you have some time to get underneath the relay box, I would try to check to see if you can find fraying or corrosion. Very frustrating.
Must be that time of the year. Mine is back also. I was so sure it was finally fixed. It is so erratic, so I'm suspecting a wire break that sometimes makes contact and sometimes not. I'm not good at reading wiring diagrams but guess I'll try to hash it out.
Have you tried replacing the N80 vapor canister purge valve assembly (P/N 06E–906–517–A)? This valve is listed as a common failure for VWs/Audis. I also have had this DTC code for some time, and have checked the leak detection pump, the vacuum hose you ID'd, and replaced this valve, but the code keeps coming back. However, after I replaced the N80 valve, my gas mileage increased significantly. For ~$20, you might try replacing it and see if that fixes your problem. For me, I'm going to check the relay next. What a PITA!!!
Have you tried replacing the N80 vapor canister purge valve assembly (P/N 06E–906–517–A)? This valve is listed as a common failure for VWs/Audis. I also have had this DTC code for some time, and have checked the leak detection pump, the vacuum hose you ID'd, and replaced this valve, but the code keeps coming back. However, after I replaced the N80 valve, my gas mileage increased significantly. For ~$20, you might try replacing it and see if that fixes your problem. For me, I'm going to check the relay next. What a PITA!!!
First thing I replaced too. Made no difference in gas mileage nor getting rid of the CEL!