Kind of ironic I just found U0284 on my 2015 Ecodiesel today
Was warmer this AM but temp dropped and wet snow covered the front end of my truck.
Nothing in stored messages just the solid cel.
I’ve never been successful getting my cheap elm327 to connect to the truck
I’ve diagnosed my Active Shutters are not cycling properly. A new ACS assembly list for $400 I can buy for $305, as dealer says they don’t offer the actuator separately though I found it online for 220$
Broke down and bought a used one off the bay but don’t know when I’ll receive it
Good luck
My U0284 appears to have gone away on its own despite the shutters being removed from the truck with the actuator only being bolted to the core support plugged in to the harness