I apologize in advance for the double post (this is in the A6 section as well) but I am trying to get to the bottom of this today. I have a 2000 A6 4.2 with 66k. My CEL is on, and after having the codes read, here is what comes up:

P1411
Manufacturer Contrl
Auxiliary emission
Controls

P1423
Manufacturer Contrl
Auxiliary emission
Controls

DTC Pending (Codes)
No Faults Detected

What should I be looking for?

 

So I took off the engine covers, removed the airbox, and did some poking around under the hood to check for obvious vacuum leaks. There is one vacuum line that runs from front to back along the right side of the top of the motor (next to the brackets that the covers screw into) This line seemed to be a bit loose, so I adjusted it, and reset the CEL. It hasn't come back on yet, could this have it?

 

P1411

Sec.Air Inj.Sys.,Bank2 Flow too Flow




P1423

Sec.Air Inj.Sys.,Bank1 Flow too LowVery well could have been the cause. With both of those faults i would expect some sort of vacuum leak between the solenoid valve for vacuum control of the secondary air and the combi valves. Or a broken pipe between the secondary air pump and the combi valves. Or a bad pump. If you have a vagcom you can run basic settings number 77 and 78 which forces a secondary air test which will tell you weather that fixed it or not.

 

OK done celebrating my apparent victory over my first CEL.
The light came back on tonight while driving in the rain (if this helps with diagnosis.) I haven't had it scanned yet, but I'm assuming that it is the same problem. Does anyone have a diagram of the vacuum hose routing, as well as all accompanying solenoids, pumps etc? I have yet to purchase my bentley manual, and would like to diagnose and repair this myself if possible. Also, where can I order some oem parts (such as the vacuum pump that may be faulty,) without breaking the bank? This forum has been a wealth of knowledge, and I appreciate all of the help from the Audi "old salts!"