I've been doing alot of hunting for information on how to determine the health of my 2012 6.7 DPF and ran across this. Just thought some of you might find it interesting, I did.
https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1026&context=ecetheses
https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1026&context=ecetheses