The DEF and SCR system is ok but if a part goes out in the system and no longer under warranty the backyard mechanic is kinda screwed.. and if the system has an issue on the road you go into reduced power mode until repaired..
Glad I don’t have either on my 2007 diesel.. it doesn’t smoke, very quite, and no black marks on the fifth wheel when towing...
I do carry a good scan tool that will read and clear any faults on my diesel should they occur.. Went into limp mode once and that puts you down to max speed of 25 mph... the MAP sensor had a tad of oil residue build up.. one 10mm bolt to remove, wiped off sensor, cleared error on OBD2 and all normal from there..
I highly recommend anyone with a diesel carry a good scan tool with them. You will only need it that “one time” in the middle of nowhere to pay for itself
Here is a nice read for those that wanna know more....
http://www.powerstrokehub.com/6.7-po...emissions.html