Def issue in '11 Volvo 780 with Cummins ISX

Last night i started getting a warning beeper and a dash display message that says 'DEF Incorrect - Service Required.' Had a significant loss of power. The company tractor shop says this is possibly a clogged Def filter. They advised not driving it so I shut it down. I have had the Def filter replaced at a company shop (a 15 min job) and thought this can be done by a roadside tech. But the company road maintenance night shift insists that it's a Diesel particulate filter regeneration failure issue that can only be done by a Volvo dealer. And, of course, I'm more than 100 miles from a dealer on an Ar. back road, with a loaded trailer. Any suggestions? Is this a roadside repair, or a tow truck to the dealer issue?

 

I fueled less than two hours before the problem occurred. So the Def tank was very close to full.

 

I seriously doubt that anything got into the fuel. But.. stuff happens, huh? Of course if any of those things got into the tank, there might be a clogged filter.