p0411 solved!
 

Hey everyone,
just wanted to share my p0411 solution (01.5 a4 1.8t); hopefully this will help someone else out that has the same problem. i know that the yellow CEL was eating my soul!~

ok, basically i inspected all the vacuum lines from the secondary air pump up to combi valve in back of head. everything was ok; no cracks or kinks.
made sure my secondary air pump was working (runs for about 30 secs on cold start, then stops as idle drops to 900rpm).

at your combi valve, there is a big vacuum hose going in on the passenger side. there is also a small hose coming out of the opposite (driver's) side of the combi valve. that's where my problem was. the hose coming out of the combi valve appeared to totally disintegrate, and it was just hanging there disconnected!
so i grabbed a fitting, put on a new hose and hooked it all up. didn't pay a penny!

hope this helps.
also wanted to thank the board. you guys got me started on this solve. thanks

Micah

RE: p0411 solved!
 

Thanks for sharing this info, I'm sure many others will find this quite usefull for their cars. Audi uses very stiff plastic hoses for vacuum lines, which get brittle with miles/time. When they crack/ leak you get that P0441 code, as I have in the past.
Glad you got yours fixed.

RE: p0411 solved!
 

great post man. I had the same code and that is exactly what my problem was. Im just happy that that was what it was and not the pump going out.Thanks for the post. Big help!

RE: p0411 solved!
 

i also had a problem with my vacume lines i had them all redone. now my combi valve is stuck open. so i gotta get one of those befor i pass smog.

RE: p0411 solved!
 

I got to give this post a bump! I searched and searched many sources with no answer to my problem until I found this post. My hose was still connected to the combi valve, but the rubber was disintegrated under the cloth cover. On visual inspection it looked fine. When I touched it, it turned to dust. Great info!

Does anyone have any pictures of the combi vlave or the secondary pump? I just recently replaced the rear coolant flange on my Audi and I bet that a hose has worked itself loose because of all the work back there. Least that's what I'm hoping.

Just curious if anyone has a picture of the hose mbertoli found or the other lines/hoses that could cause this issue.

Thanks,
Mike

RE: p0411 solved!
 

Thanks for the great info here and all around this forum. It helped me track down my P0411 problem. In my case, it was the secondary air injection solenoid. BTW, a great way to test this solenoid, and others like it, is with a 9V battery and a couple small jumper wires. Connect the 9V to the terminals of the solenoid. When you complete the connection, you should be able to hear and/or feel the solenoid click. When you break the connection, it should click again. My solenoid passed the resistance test, outlined in the Bentley manual, but that only tests the coil of the solenoid. It failed my click test, so I knew it had seized up – a common problem with solenoids. Once I removed it, I was able to free it up by just banging it on the bench a couple times – a common fix for solenoids. My click test verified that it was working again. I then cleaned it up by spraying contact cleaner through all the tubes, followed by some compressed air. I put it back on, and it’s been working fine for about a month now.

How does one go about fully troubleshooting the secondary air injection system? I would like to be sure what the problem is before i go and buy a new combi valve or air pump etc. mostly the combi valve, how do you test it?

Picture attached
 

Hello,

I was able to find the problem by using the post on this thread. Here is the picture shows where to find the tube. Hopefully it will help someone.

https://doc-14-04-docs.googleusercon...f1nevgidok0rc2

I cannot see you picture, can you post it again? I am trying to fix this same issue.