[Taxman]

300 miles is not enough warning?

When fuel stops are more than 300 miles apart, yes.

But I thought it would say "35% full" before it would say "300 miles remaining".

 

[Taxman]

The DEF tank does not need to be filled as often a the fuel tank. It is not like fuel will go 700 miles but DEF only 300. The opposite is the case.

Right.
So there's no reason not to tell the driver 'I need DEF in 1000 miles', so that the driver can include it in his next fuel stop.

 

[Taxman]

John, you're not getting my point.
I'm saying if it's going to warn you, it should give warning in ample time so that you can take care of it without making a special stop just for the DEF. It should be programmed for driver convenience, not just to make the driver satisfy the car's needs.

Since the logical way of dealing with the DEF is to include it in your next fuel stop, 300 miles isn't long enough if you don't plan on buying fuel in the next 300 miles. I don't want to be rushing home on December 26th and get a warning "fill DEF within 300 miles" when I'm 400 miles from home, had my final fuel and meal stop half an hour ago and have to drive to work tomorrow morning. That's just stupid software making my life more difficult.

 

[Taxman]

Ideally, I'd notice when it went from 100% to 37%, and plan to make my next fueling at a truck stop with DEF pumps. But I'd appreciate it if it would pop up on the display when it dropped below "full". Then I'd push the OK button to dismiss it, and try to remember to pump some DEF next week.

Actually, in an ideal world, it would read 50% at half full instead of reading full, but that's another case where they put protecting the car from idiots ahead of making it convenient for knowledgeable drivers...

 

[Taxman]

There is a 1000 mile warning but it’s easy to miss because the message appears once and then it’s gone.

You don't have to manually dismiss it with the OK button like you do with 'service airbags' or 'tire pressure low'?