Check engine light come on after egr bp with register mod.. please advice...

i have an 05 freightliner century, 515 hp 13sp and got problem with egr vale. after i read one thread in our forum i designed to try. First trip engine running good, no more egr vale problem but i got check engine light come on at the second trip ( at 6500 mile after mod): "Eng noresp 128s146 07"
i just try to know if anybody have same problem like me? for myself i dont really know if this code belong to one of the parts with egr system or not... i am still running right now with no problem but this code still active.
how far the mod egr engine doing anyways? i mean how long ur mod engine doing so far...
Thanks alot and have a great weekend everyone...