[navybanker]

Don't let a GM dealer tell you your "DEF quality is poor message" is because you didn't purchase from them. There are GM web pages that specify owners can purchase at truck stops and other stores besides GM dealers. Google it. I had to show it to a service department. And, there is an inexpensive test device for DEF similar to a battery tester that a dealer needs. Now, this particular dealership has one but I don't darken their doors. I am not an expert but have a lot of experience with dealerships across the country because of emission problems! Dieselplace.com is a lot of help before you talk to the service departments.