I have had the DEF level vary day to day. I have had the software flash which did not help. I also run a iDash and it can show DEF tank level and is a more accurate percentage based indication. What I've noticed is that it seems to slosh quiet a bit. Acceration/braking will cause the level % to vary 20+ percent. Since I have been watching, the DIC went down to one bar (and stayed there for a few days) while the iDash still showed 49% while stationay. Filled it at the local truck stop and put 4.3 gallons in. I dont think the truck has any idea how much DEF it has.
2020 Denali 2500 Duramax Crewcab 4x4
Last edited by sdelam; 12-27-2019 at 07:32 AM.