Messages like this one are what make modern trucks a pain to drive. There's no purity standard for diesel exhaust fluid. There's only whatever the trucks are programmed to accept, and whatever's available. Back when I drove a Volvo, I used the DEF pumps at Flying J, figuring they were safe. After having the tank cleaned out due to "impurities", the Volvo service folks said the trucks ran best on the jugs they stocked at the dealership...which, strangely, were the same jugs as Flying J. Hell, my KW has had the SCR Malfunction light on since about a week after I got it, and I only use DEF from the pump at the yard in Toronto. Fortunately, the problem doesn't seem to be hurting the truck, so the light persists.