2016 Ecodiesel Code P249D

[Chargermann]

Anyone have any dealings with code P249d ? Only thing I get (when I Goggle it) is "Closed Loop Reductant Injection Control At Limit- Flow Too Low" ? Anyone know what that is and how to fix. I am a service text by trade and can usually fix whatever if I know what to fix.

 

[carlhenry]

when was the fuel filter last changed

 

[Chargermann]

Changer it last month when I did the Oil and cleaned the DEF injector.