Originally Posted by Roadkill
Mine threw this message over a month ago (caused by P20E9 & P204F). I had no time to deal with that bullshit, so I recorded the codes and cleared them. The idea was that this is an emissions system issue rather than something important, and if it weren't transient the code would be immediately pending and inevitably reappear promptly. Because it was an emissions code, after clearing the codes I had to drive it and cycle the engine before the MIL finally turned off.
Those "Service DEF" codes (P204F/P20E9) never recurred, but there was a patch released yesterday as a RRT 14-107/TSB 18-023-15
~6 months after I experienced the codes the fix was released. I guess it just corroborates the "don't freak out" approach to issues on the WK2 EcoDiesel.