On my nuvi 3490 GTM36 work and after i change region 140.bin still work,i add back original region 140.bin and still work.
I compare all region before and after i change region 140 and all region ar the same,no change to other region (reg 41 is the same before and after change)
On nuvi 3490 original no change of region 140 GTM36 dont work.
Also nuvi 1490 dont have data in region 140 and GTM25 work like charm but GTM26 dont work.
I will try to find report of Garmin where is writen for error of searching TMC data on GTM 26 and 36.

@ gc_geforce
If you add GTM35 to your nuvi TMC will work.
I see nuvi series 2xxx out of the box and GTM36 wont find TMC data and after replacement for GTM35 all work.

p.s.
This is mail from Garmin:

Currently, the problem sets GTM 36 and 26 for a given software TMC receiver does not work properly. We work on the elimination of it. You will need to wait some time to resolve this problem. Thank you for understanding