Sounds like yours got 1100/15 = 73 mpg (or maybe only 55 mpg is 20 used for calc) no way it should use 15 or 20 gallons. Yes indeed i have a 2020 silverado 1500 with a 3.0 duramax.
That's 3 or 4 fills of the 5.3 gallon def tank!
Service emission system 2021 3.0 duramax. I had that happen at 98000 km on my 2012 gmc 3500hd, and the dealer replaced the def tank, the heaters quit, now another problem, at 125000km service emission system on dic, so, dealer changed out 2 nox sensors and couldn’t get it fixed and now want to change the whole exhaust system, i’m not letting them do that, so, here in new brunswick we have no. 4% of 92 is less than 4 gal. I have 30.000 miles average 32.5 mpg.
New tsb issued for duramax 3.0l lm2 and 6.6l lp5 diesel p206b, emission & exhaust fluid errors general motors is addressing an issue that may cause check engine lights on 2020/2021 diesel silverado and sierra pickups. I owned 6 18 wheelers 50 years on n american roads canada alaska and 48 i love this vehicle.