I am having the same issue as everyone else here. 2021 Silverado with 3.0L Duramax, towed a 4500 lb trailer a total of 650 miles and used almost 8 gallons of DEF. Took the truck to 2 different Chevy dealers and both said the system is working properly. Despite also stating the system should only use 1% - 2% DEF per gallon of diesel. I used about 50 gallons of diesel on the trip which should only be a gallon of DEF On the high end of Chevy’s own estimate. Hell even if I doubled their estimates it should have only been 2 gallons used not 8… Neither dealership could explain to me how the math was so far off.
Not sure what the point of having a diesel truck is, if I can’t tow with it…
