Welcome! Do you get a lot of highway time, rather than city driving to allow the truck to perform a proper regen? Does it ever warn you, exhaust 80% FULL, etc?
Welcome! A pretty common problem with the ecodiesel. I would recommend searching "throttle control" or "ETC", sample: https://www.ecodieselram.com/forum/threads/ecodiesel-service-electronic-throttle-control-message.203/
Welcome to the forum.. Check out this section for more information on potential tuning/vendors.
https://www.ecodieselram.com/forum/forums/ecodiesel-performance.28/
Welcome! We've got one member here that went over that amount. All in all, have a read around the forums, plenty of info here around ways to help overcome some issues.
Welcome! Unfortunately, I can't find anyone else that's posted about that code here. I would almost bet though you have a bad sensor that will need to be replaced. I'll move this into the engine section so hopefully it might catch someones eye there.