California is literally the only reason the 6.7 cummins in the dodges have DEF to begin with. Few years ago, in our test cell, the CARB board guys came in, that 6.7 was the only diesel of any of the big three to meet the pending emissions requirements without DEF. Ford and GM engineers were stunned. So we at Cummins got caught off guard a bit when both the CARB and EPA came out and mandated that all new diesels HAD to be equipped with DEF even if they met emissions without it
