Code 3567 and derate.

[JM84]

Hello, this truck I’m working on derated for scr fault. I plugged into it a day after it parked. Had inactive code 3567 and code 3714 for derate. Both said inactive but still had warning in dash.

I deleted the codes and they haven’t come back yet

What is the best way to troubleshoot this?

Also I’m a little confused on dosing valves.

Are there two at the filter for DEF?

Always thought there was only 1 on def systems