Hey guys I am new to the forums but a long time audi owner. I have recently picked up a 01 C5 A6Q with a 2.8 30v. About a month ago I got a CEL but the car itself was running just as normal before the CEL came on. I do not have vagcom to see what code was being thrown but my SAI pump was running even after the car was shut off. I checked all the vac lines and none were brittle or broken. I then just disconnected the battery and the code was cleared. Then again earlier this week I got the CEL right in the middle of my 40 mile commute just like the first time. I got home, shut the car off and the SAI pump was running again. I did some forum searching and I am wondering if it could be the J299 relay that resides in the "E-BOX". I wanted to see if anyone else has had the same experiences. Thank you in advance for you help!

What was the CEL code? Did you check the plastic tube connecting to the air box from the SAI pump?

Unfortunately I do not have access to a scanning tool (i.e. vagcom) and yes I have checked all lines and they are fine. There is no air leaks from either the lines or the pump itself.

First of all, I would recommend picking up a cheap VAGcom off ebay. You can really troubleshoot better with one.

The reason that I ask about the SAI lines, not vacuum lines is that they tend to get brittle and break sometime. It will trigger SAI pump to run randomly.

It may be the relay as you noted; however, you need proper tools in combination with proper repair manual to figure out what is going on.