Thanks in advance for any help on this.

Daughters car located in SLC Utah Audi A4 1.8T model year 2001

We had the temperature sensor replaced a couple months ago and just after that the infamous air injection code popped. P0411. I happen to be out here this weekend and was trying to trouble shoot it.

Found a small vacuum line that plugs into a fitting on the right side of engine as you are standing in front facing it....about mid way under the intake. It runs from where it plugs in along with a larger hose and runs under the intake to the rear of the cylinder head near fire wall. The end near the fire wall is not plugged into anything and is just dangling there. I'm sure this is the culprit and was probably left unplugged when they worked on the temp sensor.

I have include a link to a video showing the line. I need to figure out where it plugs in.

Heading home on Monday so I got to fix it today.

Thanks for any advice.

 

I think I may have answered my own question by searching forum and finding link to other site referencing 1. 8t in VW passat.
See link
DIY: how to replace 1.8T AWM Vacuum Hoses

 

I don't even need to see the video. I had the same code, with the same problem.

Look behind the engine head and you should see that three way crankcase breather hose bullshit. Follow the pipe that comes out of the left side of that 3 way hose and (still behind the head - in between the firewall). Before that pipe beds, underneath it, you'll see a silver diaphragm. The vacuum hose plugs into the right side of that. It's just hard to see the nipple, because there's a hose, or wiring, or something running directly over it. It's kind of a bitch to get to, but it's not that bad.

Let me know if I can help further.