A few weeks ago my 2015 F350 6.7 Diesel with 14000 miles on it start throwing a check coolant additive code. took it into Ford and they said it is normal for this to go off at 22000 miles, every 22000 mile! mine just went off early for some reason, it cost me $83 to have them turn it off, My truck it 7 months old and I have to pay to have them turn off the code. they said it goes off so you will bring it in so they can check the additive to make sure no corrosion is going on, but I have to pay for them to do this. I guess this bumper to bumper warranty only covers what they want to cover. anybody hit this code yet?
