A Chin

I've experienced similar issue when towing 7200 lbs. Gauge reads 60% and then after 30km or so, it's showing def tank empty and about to go on low power mode. Mentioned to the dealer and they said "def fluid gauge is not a float style gauge and it could take a few ignition cycles to get an accurate reading and also if the level is just above or below a certain calibrated spec, it may give false readings". It looks like its on bulletin 20-NA-082.