I thought the DEF message was supposed to pop up when you are under half full?? I was just checking my system info and selected the DEF fluid and it said DEF under half, I would have hate to have the truck not tell me the status of my DEF and then go into shut down. They really should have just put an onboard fill gauge for fluid level.

 

I thought the message comes on at around 800 miles to go.


Sam

 

How much is the stuff? I heard around $20 for 2.5 gallons?

 

It does not tell you anything until you have 800 miles to go or less. Sam is correct.

Only way to find the below 1/2 message is to run the system check.

 

The DEF is around $20 for 2.5 gallons IF you buy it from a Ford dealer. $12 for 2.5 gallons at Oreilly's and NAPA. $3 a gallon from the DEF pump at Pilot truck stops, if they have a dispenser.

 

At about 3900 miles, I got the "800 miles worth of def left" or similar.
After that, every time I cycled the ignition, I got another message telling me how many miles of DEF were left.

In addition to other places, Pilot and Flying-J truck stops have DEF for about $13 for 2 1/2 gal jugs.