Truck had an active fault for DPF soot load high and SCR conversion efficiency low. After about an hour of Regeneration and approximately 5 gallons of diesel fuel burned the soot load fault went inactive. Might be a DEF ball in ATD preventing the DEF from reaching the SCR Catalyst or defunct NOx sensor. Conversion efficiency has to be 85% or greater at all times to make the fault go inactive. I just replaced the cylinder head from a dropped valve which caused the engine to run dirty so I may try another Regen to see if NOx output from the SCR cleans up some more. I don't think I ever will own a EPA10 or newer diesel engine because of the constant ATD issues. Here's a pic of some of the ATD instrumentation on my diagnostic laptop.

 

 

Had another Detroit DD15 with 3 injectors failing. Replaced the 6 pack of injectors and babied the Regen to clean out the fuel soaked ATD  trying to keep it under 1400*F. Here's a shot of the screen showing NOx out is higher than going in due how fuel soaked the ATD was.

Gotta love them Common Rail injectors.