6.7L Power Stroke Engine and DrivetrainDiscussion of the 6.7L Power Stroke diesel engine and drivetrain in the 2011-Up Super Duty trucks. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 6.7L Power Stroke engine.
I let the def fluid run low on my truck. At 100 miles left, a screen came up stating in 100 miles truck will be limited to 55 mph. At 70 miles left the screen turned to less than 300 miles left. The next time I started it it said less than 800 miles left. I went to fill the tank and it is full and will not accept any def. How can this be possible?
Your DEF guage is a very simple design. Basically 3 sensors. Full, Half and 800 miles to empty.
I can see difference in parking, angle of truck etc causing some small variances in the readings ( say the 100 to 300 mile reading) But there is no way a leaning truck is going to now read full vs empty.
As far as it not being able to accept any DEF. Either somebody filled it for you or you've got kink in your fill hose.
11 F350 CC Lariat SRW LWB Tuxedo Black
B&W turnover ball
I say there is a problem... Normally I would say do not worry about it and you have a truck that doesn't use DEF - however, this is one problem that can leave you on the side of the road... Speed limiting to 55 mph is while you are driving, eventually it won't let you do anything other than idle.
First, did you get the NOX recall done? There were some potential faulty NOX sensors and a new calibration out.
Second, whether you did or did not I would let the dealer take a look.
I have noticed that my 550 will read "800 miles" if I fill it to the top. After a few miles it resets and works properly. Not saying you don't have a sensor issue, but it seems the sensor thinks full to top also means "empty"