Anybody know a easy way to check code Po 411 on my 2003 A4 ...I found cracked check valve replaced it light still on checked hoese ECT.. Looks Ok ..I read all the Potential Causes and looks like I need to be a Audi tech to find it..Runs good.. I trying not drive it to the man.... He drives a new lambo.( Wonder how he makes his money ?? off people like me..Help..and THANKS

 

P0411 is an indication of a MAF sensor (mass air flow). A common cause is the vacuum lines conneted to the MAF. A leak or worn vacuum line will throw a P0411. Check the lines going to the MAF (near the air filter). If the lines are good, then replacing the MAF should solve your problem.

 

That check valve will throw that fault. Replace it. Also look around for broken vacuum lines and replace them as well while your snooping around

 

Thanks.I went on line and looked it up and all I could find on PO-411 was ( SECONDRAY INJECTION SYSTEM ) it blows hot air into the cat and heats it up..Why ???? I found two check valves looked cracked to me... and replaced them turned the check eng. light off was good for about a week and the light is back on..Smoke test is what I keep hearing to do..Runs good I guess I do a smoke test at the shop...The A-4 has LOTS check valves @ about $40 Ea. Smoke test...Thanks..