Newer diesels with DEF injection (e.g. 2011 Siverado 3500HD Duramax...mine, for instance) can be problematic in terms of spurious (false) warnings that can still ultimately put you into limp mode. It's a design problem and the dealers can't provide a permanent fix. This is the first summer using my TC and it seems I've seen more dealers than campsites....sometimes 200 miles away out here in the Great Basin. It's been a huge damper on my plans for boondocking this summer.
Though widely discussed on the Duramax forum the dealers and GM forum representatives profess ignorance. The only thing the dealer can do is reset the computer to clear the alarm...until the next time.
I have decided to delete my DEF system, as many others have done out of sheer frustration at there not being a fix forthcoming from GM (much less acknowledgement of a problem). There's a cottage industry out there deleting the DEF systems.
Between my frequent trips to the dealer, the truck has been a real workhorse. I just wish I could confidently drive more than 200 miles without a problem.