Not new to Diesel, but new to Def. 2019 Silverado 2500 hd, 6.6. First run in with Def was at the end of a trip hauling my trailer. Got a low def warning, then a second one. Put in 2 1/2 Gal of Def. and all was ok. Here I am several months later and my def sceen is showing a percentage number only. In reading the owners manual I ge the feeling it goes from Def ok to the percentage to Def low but it was not really clear. Anyone with an answer?

 

There should be a diesel supplement book in addition to the owners manual. Read through the info on DEF system warnings and instrument cluster operation (specifically DEF gauge reading) to know what to expect.