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

[Rawze]

3567 is saying the DEF doser injector is unplugged. If it is inactive then clear all the faults and se if it comes back. If it does then it can the doser injector going bad.. but is more likely to be a wiring harness/connection issue somewhere.

BTW: There are typically 2 doser injectors in most aftertreatment systems. One is behind the turbo to put FUEL into the DPF to clean it... and another one to inject DEF FLUID into the Decomp tube to make tyhe SCR element function properly.

[JM84]

What is the best test I can do to rule out doser valve?

It looks like I got 3 doser valves? Maybe I’m wrong.

One just past turbo. Then two on outside of the filter housings?

[JM84]

Nevermind I was looking wrong spot. Found them both.

I’ve ran a regen with no issues.

Wiring issues most likely?