Introduction & P205B code

Ok, first post and new owner of a 2015 Chevy Cruse diesel. The wife and I both, enjoy this car! We have 27K, and keep getting this........P205B code, telling me that the DEF temp sensor is out of range, or at least that is what DashCmd says it is.

Can those of you, more knowledgeable than I, shed some like on the cure for this curse?

I really miss using the remote start............!