Poor DEF quality no check engine light

[RollinCoal]

Bottled def is ok but you cant let it sit, its water based and will evaporate and screw up the concentration,
If you need the cummins def level fix send me your esn Ill see if its available for your truck
But it really helps to keep the def tanks full, As the level drops the def will crystalize in the tank and can cause the level sensor to get stuck and or not read correctly