Need some imput from others on my DEF warning.

My DEF low light came on, dumped a 2.5 gallon jug in and left it at that. I got about 500 miles out of it and the light came on again. This time topped it off. The light came back on after about 600 miles. It will show the warning when you start the truck and I just hit the "ok" button and the screen clears. Well, after about 2 starts, the warning light didn't come back on again when I started it. I did not reset the button, just hit "ok" to clear the screen.

It wasn't parked on a hill, so don't know why it would come on for a few starts and then never again. I topped it off again, and it only took about 2 gallons.

My 2011 seemed to get about 4-5 k out of a full tank.

 

Since you top it off the last time I would think the sensor is bad. Did you give a couple of day to reset?

 

Takes awhile to reset it.

It is best to fill it up completely when it gives you the warning.