I installed a 21" wheel on my 14sgs. I used Michelin tires (stock rear size 120/70/21 frt), I don't have a thunder max module. Everything works great, no lights flashing. I must be lucky..

 

Have you gotten out and logged some highway miles? I think the rule of thumb is once you go over 55 mph and keep it there for a few minutes, the codes will appear when you fire the bike back up after shutting it off.....
Also sometimes too much anti-seize on the ABS bearing will throw a code as well.....

 

what size dunlop tire you need in front to not throw abs codes,thanks

 

If I remember correctly a 130/60/21 will result in a lower profile and allow you to not to have to run the Thundermax - and I think Dunlop is the only one currently making one in that size.
Dunlop makes a good tire and the ones that are stock on HD, but some of us prefer a better riding/handling tire thus have switched to other brands
If you've not yet read up on tires, it's a topic that gets a lot of attention (like exhaust pipes. oil, etc) - everyone has their own favs...

 

I had a 21 wheel and wrap fender from HogPro installed a few months ago.. My set, front and back came packaged with Pirelli Night Dragons. They've been great. Front and rear suspension will be upgraded from stock in the next few months. NO ABS issues; codes or otherwise.

 

I have a set of PM heathens. They came with ABS axles. No flashing anything for me.

 

I've logged 12000 miles on this set up at speeds up to 100+ without problems.