MIL message " service emissions soon"

I have a 2012 LML and the" service emissions system, will derate in 99 miles " came on. I repaired the reductant heater that caused the issue and had a stag 2 tune put in, but he message will not go away. there are no trouble codes and the message resets back to 99 miles after shutting the truck off. I have been running the truck for 2 weeks with no other issues, but I can't any other function on the display. I travel for work and need access to my mileage and trip display. I am new to the EFILive tuner, so any help would be appreciated.