2013 duramax with exhaust quality low issues. Took...

2013 duramax with exhaust quality low issues. Took truck in for diagnostic-$155. Needed a new turbo came solenoid, 2 new NOx sensors, and a DEF heater...they wanted $4,300 to do it. I took the truck home, spent $600 on parts and did it myself in 3 hours. Check engine cleared but still had exhaust quality low. Took it to a diesel shop, they forced a regen, didn t clear it. Took it back to this dealership, they forced regens, ran tests, said everything is passing and don t know why it s the message isn t going away. They say, well our next step is to change the exhaust fluid because you re using the wrong brand. We ll change it and run the test for $740. So now here I am picking up my limp mode truck again because they can t figure it out, and I will change my own exhaust fluid for $20 and 1 hour of work. Delete maybe?