My 2015 is ( code P208D and P208A)

[BabbsJerry]

And I get this warning every time i start truck and drive down road.
"SERVICE DEF see DEALER Truck will reduce speed to 5mph in 50 miles"
What is going on!!

 

[Ecopete]

And I get this warning every time i start truck and drive down road.
"SERVICE DEF see DEALER Truck will reduce speed to 5mph in 50 miles"
What is going on!!

If the DEF tank isn't on empty, then obviously it has issues with the system. The def injector can clog and can be cleaned, then run your system at 50/50 DEF and distilled water to prevent it from happening again. 2015 doesn't have a DEF quality sensor so that works