I am in a love/hate relationship with my 2015 F-350 6.7 diesel truck. For the first 11,000 miles I loved the truck and NOW I hate it, it has been in the shop four times in the last month, it has gone into limp mode 4 times, DPF and overheating. every time I get it out of the shop they say it is fixed. it now seams that every 200 to 250 miles it has a plugged exhaust filter, drive to clean. Towing a load and driving to clean doesn't do any good, driving to clean when the truck is empty will clean the filter. Seams to me that Ford has no solutions to this problem, why did it run so good for the first 11,000 miles and now it is just a $70,000 paper weight. All the info I have been able to research is to delete the exhaust system and install a tuner, if that is the solution why did I buy an extended warranty (modifying the exhaust voids the warranty)

 

Have similar problems with larger diesels that idle a lot. A regeneration cycle is required to burn off soot in the system. Smaller ones can get by with a "drive cycle" where sufficient heat is generated to get rid of some of the soot. A higher RPM is required to generate the heat required . DEF fluid can degrade if left open too long , good for long time if not opened.

 

DPF and DEF are separate systems. Drive to clean has to do with Diesel Particulate Filter, but thanks anyway for the info

 

Those two systems work together. If either one has a problem , it affects the other.
Just out of curiosity , are you using anything other than "Ultra Low Sulfur Diesel fuel"?