How To Clean Def Doser Valve

I have a 2012 Cascadia with Cummins ISX and I'm having nonstop aftertreatment issues. I'm $3000 in so far and yesterday my truck went into 5 mph derate and had to get it towed. The first few times, the def light kept blinking and check engine light would come on, then I would do a manual regen and after half hour the check engine would go away. I took it to this shop and they said the fuel doser wasn't working or wasn't getting hot enough to burn the soot in the DPF/DOC. Now they're saying the def doser isn't "spraying correctly." So my question is aren't those two things the same thing? I'm wondering if they changed the doser and messed something else up.
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well doser injector is one thing, it sprays a bit of fuel into the exhaust as it leaves the turbo to help burn in the filters. The def doser is probably spraying the def fluid. Idk for sure though, never owned a def truck. But I think that's what it is. 2 separate things. One sprays diesel, one sprays def
No. The doser is at the entrance to the scr not DPF. That's what we call the 7th injector.
7th injector injects diesel fuel to heat up the DPF.
Doser injects ammonia into the scr from the def tank.
Any and all after treatment issues will cause a check engine and set you into derate. EPA norms my friend.
They are two different parts.
One injects Diesel fuel after the turbo, before the DOC (Diesel Oxidation Catalyst) to raise temperatures to do a regeneration.
The other injects Diesel Exhaust Fluid after the DPF and before the SCR (Selective Catalytic Reduction) to reduce the NOx in the exhaust.
What codes did you get on the dash?
I just got two derate codes. Before I fixed the fuel doser I would get aftertreatment codes. One for too many regens and one for SCR Catalyst

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