Need help understanding "New" codes in Paccar engine.

Rush Truck center told me that they can not do a snap test with any part of the exhaust removed because the engine will not run with no back pressure in the DPF. I thought that sounded odd.
They did do a flow test on the (latest) doser (i have had two put in it) .
I have tried to get these guys to start thinking in terms of ECM or internal engine issues. They are all stuck on after treatment because that is what the Davie says the problem is.
They can't wrap their brains around the idea that the engine could be causing the after treatment issues.
I am leaning towards another shop but being Paccar, I only have a few choices and going to another Paccar shop means that the Rep will probably be the same guy or same group of guys. I need a shop that takes the Paccar Reps info with a grain of salt and does their own diagnosing. Im tired of paying parts changers then hearing "thats what the Paccar rep said to do".

 

I will do an oil sample now, good idea. thanks...

 

Current codes.
P1496 EGR Disabled
P151A After-treatment system - Misuse detection Level 1 ( I was told by highway patrol that I had to get moving, I was being escorted by CHP and they didn't want me blocking the 405 in L.A.) I stopped a manual regen in progress.
U1011 CAN Communication - Hardware or software malfunction on E-CAN
P1508 Aftertreatment system yellow warning
P3789 EAS-3 DPF Soot level high
P3792 EAS-3 DPF regen switch - Used in soot level 1 or higher (probably when I forced a regen on the freeway)
P3812 EAS-3 NOx sensor after catalyst - CAN communication error.
P0219 Engine speed too high

 

No, they won't let me talk to them. I keep calling and giving the parts changers ideas about what to do. It feels like Im the only one willing to try to find the cause, they all want to address the effects of the issues, like cleaning/replacing DOC and DPF because they keep filling up... WHY DONT WE FIND OUT WHY they are filling up in 1000 miles?

 

I just called and told them to do an oil sample... They never thought to do that to see if we really are getting high soot levels or is it just a bad sensor? So, 10 hours of labor later they have my manifold off. If my oil is clean and no soot in the manifold, I'll bet we find a bad soot level sensor.

 

3792 was just telling me that I did a forced re-gen i think. Its never been on before so I don't think its the switch. Maybe I pushed the button down to make sure it wasn't already down. But either way it was not doing a re-gen and I had to force a parked re-gen in the middle of the 405 freeway because it went to the red on the gauge and was backfiring and had no power (not a de-rate just low power). I could only do about 10 minutes then the cops said no matter what we had to move. I was 16 feet wide and blocking half the lane so I couldn't argue with him. I knew i shouldn't be interrupting it but had no choice.