[a430vaudiguy]

Mine was coded 17 when I installed my EU RNS-E and we coded it to 21. No luck with getting it to work. So reading more and using the vag codes from this page http://audi.ogdenlabs.com/vagcom.htm We coded it to 5 and it started working as soon as the RNS-E was turned off and back on.
I also used the knowledge base & quick links info provided by AudiA4B4US.

 

[a430vaudiguy]

vag codes for RNS-E in red dis

I was talking to the person who coded my car after the Nav install a couple of days ago and he told me he found more info as to why the 21 code didn't work on my car, but the 5 code does.
The 5 is for the red dis and the 21 is for the color dis. I had the red dis at the time and when I install the color dis, I should have to get it coded to 21 to work...I'll soon find out.