Sounds like your getting the run around. I would make sure to keep all documentation in case this next dealer can't figure it out. Then call Ram customer service and open a case.
Your only option is to drive to another dealer closer to you that has a diesel tech on site. That code comes back as an emissions code, here is a workorder I found for another EcoDiesel that had the same problem:
PUNCH #1 AND #2 CHECK ENGINE LIGHT ON . CODE p2OEE-00 SCR NOX CATALYST EFFICIENCY...
Good info Max. So far the cold isn't affecting the #EcoDiesel at all. Although, most modern diesels handle the cold well now. The block heater makes a huge difference. I need to get a timer to kick on about 3 or 4 hours before I leave so it doesn't burn as much electricity.