CM2350 ISB6.7 B101 EPA13

[Madd Scientist]

Hello everyone, thanks for allowing me to join the community. I have a 2014 freightliner Business Class M2-106 thats making me insane. I was hoping for a bit of guidance. I have 2 active codes 3714 & the notorious 3712. Both stay active all the time, its in a 5 mph torque derate & there are no other active dtc’s. Ive used Cummins Inline & Guidance app to update the software to the latest update DT90413.10 from the previous DT90413.08. The truck ran fine for 3 months and now its got the same 2 dtc’s active. No other dtc’s at all. After combing over the data i noticed a few things this time. We replaced the Outlet Nox Sensor because it was reading 1402ppm and the inlet was reading 180-250ppm. The DEF DOSER VALVE STATUS READS “dosing” even when its clearly not. I with the current derate i cant even get it to run the AFT DIAG TESTS OR DOSER VALVE TEST. Also the SCR INLET & OUTLET TEMP SENSOR VOLTAGE remains at zero even though its reading 900F-1200F within 10 minutes of cold startup. Cummins says to run the software update again but it keeps kicking it out and saying it already has the latest software. I know im not the only one whos had this issue but before I drop $3K on a new ECM at my nit so local Freightliner dealer i wanted to see what advice you guys might give. Thanks in advance.
Within the last 3 years its gotten a new aDEF HEAD SENSOR & tank, a new DEF pump assembly, new doser & Decomposition tube cleaned with all new seals & clamps. Outlet nox sendor, EGR & intake cleaned, EGR PRESSURE SENSOR (was cracked) & egr differential pressure sensor & passages cleaned.