I think this is the code we had when the in-tank heater in the DEF tank went out. They had to replace the whole tank, but it was under warranty. You're probably OK until it gets cold enough to freeze the DEF. Hopefully by then, you can find out how much the repair is or delete the whole system. A delete would probably be right under a 1000 with exhaust work, so hopefully a repair wouldn't be over that. But it is the dealer, so Im sure it will be nasty.
After a bunch of research and a few inquiries it turns out that this particular code (P20BD) specifically indicates the DEF heater circuit that is embedded in the DEF feed line from the tank to the DEF injector. It is a roughly $225 part from Mopar discount sites, but evidently is a bit of a pain to install. Ordered mine today and will be installing sometime in the next week or two.