Just got 2 codes this morning for my SAIS. Low flow for bank 1 and 2. Havent looked under the hood yet to check things out but Im wondering if there is a relay for the pump somewhere or a fuse that I should check first. I have doubts that its carbon build up since both the banks threw codes at the same time.

 

It's probably the pump itself as they are a known problem. Search the forums for replacement instructions and elimination options.

Good luck!

Bob

 

I would check for vacuum leak first.

 

73.8% of the time a secondary air injection code is due to bad vacuum lines, but if it throws codes for both sides the probability of a bad vacuum line drops to about 50% - The vacuum hoses are cheep so start there and then the fuse - only look at the pump after you've eliminated the cheep stuff.

 

Ill start ripping it apart tomorrow. I tried to find fuse for it on the main panel but its not there. Must have a relay somewhere ...

 

In my search for knowledge about this SAI I found this.

http://www.vaglinks.com/Docs/Audi/C5...aintenance.pdf

Its part of a bentley manual that shows everything you need to know about the SAI on the 4.2L.