DEF fuel level

[Jeff Holtkamp]

Is it a common problem with the def system in a 2011 5500 truck where the low def light comes on even with 20% in the tank?
I've added and the level doesn't always change. My local dealer keeps saying def deteriation or contamination.It just started doing
this in about the last 6 months.

 

[jus2shy]

Are you adding enough DEF to it? Manuals for all 3 manufacturers recommend adding a minimum of 2.5 gallons of DEF to get it to change levels. It's not a float gauge, but a series of sensors that detect the presence of DEF. The computer kinda guesses how much fluid is left when the fill level is between sensors. If it was the quality of DEF, I believe you would get a different error code for that.

 

[Jeff Holtkamp]

Are you adding enough DEF to it? Manuals for all 3 manufacturers recommend adding a minimum of 2.5 gallons of DEF to get it to change levels. It's not a float gauge, but a series of sensors that detect the presence of DEF. The computer kinda guesses how much fluid is left when the fill level is between sensors. If it was the quality of DEF, I believe you would get a different error code for that.

Yes 2.5 gallons were added and the level didn't change. It was at 23% and says X amount of miles to shutdown.

 

[Newsa]

In my 2013, 2.5 gals will take the needle from near empty to 3/4. But a 2500 def tank is smaller than a 5500

 

[Larry Willard]

On my '13, 2.5 gallon added when the gauge reads 1/4 or less will take the gauge to almost full. The gauge however sometimes take a few minutes to move after restarting the truck.
Larry