Hello,

I'm new to the board and new to Audi. I just bought a 2003 Audi A4 Quattro 1.8L last week. I've had the car for 8 days and check engine light came on after about 3 days of owning the vehicle. Obviously, I'm not too happy. Anyway I went to Autozone today and got a diagnostic test. I was just wondering if anyone could offer me any help on the code I recieved. It's : PO411. I guess it's something to do with the air injection system. Anyone have any idea what it's going to cost me to get this fixed? Thanks.

 

I have a 1999 A6 quattro 2.8. I have had this code on and off for a couple of years. Each time I had the system checked, the dealer said everything tested ok but that I might need the combi valves changed, but they could not say for sure since everything tested ok. I have not fixed it yet, but I have discovered that the combi valves are vacuum actuated and the vacuum hoses to those are the most likely culprit. Look into changing the vacuum hoses to those valves. That is what I am going to do first. Its a safe and cheap fix to try first. Also if you are not running preimium fuel it could throw things off. Good luck.

 

I have battled this code, there is most likely a vacuum leak. I had to change some of the small vacuum hoses, and then I had a leak on the breather hose. Check all of your vacuum lines and see if you can get the code to turn off.