DEF Warning in F350

VinnyP wrote:
While on a trip a message popped up "def range 400 miles." When I got home the next day the message was down to 200 miles. I added DEF but the message remains. I'm down to 100 miles and worried that the engine will shut itself down if it gets down to 50 or so. If I press the OK button it goes away but comes right back when I start the engine again. Trying to avoid a trip to dealer. Any ideas?

Hi Vinny,
I had the same earlier this year. Mine was the "heating sending unit" that went out. The unit monitors the level and keeps the DEF warm.
It was roughtly $300 with parts/labor at the Ford dealership.

Most truck stops have DEF at the pumps so you can fill up the truck's DEF tank. Some Shell gas stations have added DEF at the passenger vehicle pumps and they use a smaller nozzle than the truck stop pumps which makes it easier to manage the flow.

Towing I get about 750 miles per gallon of DEF and know when I need to add more to the truck. DEF usage is a percentage of diesel burned so less is consumed when not towing and the vehicle's fuel consumption per mile traveled is less.

These are "emissions control" devices and in some states (like California) it is covered for far longer than the standard manufacturer's warranty by law. Check your state's laws before paying the dealer for work on the DEF system.

Good part about DEF is that you can go longer between oil changes as it greatly reduces motor oil contamination from soot.

The "Under 1/2 Full" message is available from the information center. Select "information" then "systems check" using the buttons on the steering wheel and select "exhaust fluid". The message will either be "exhaust fluid level OK" or "exhaust fluid level less than 1/2". This is what comes up when 2.5-3 gallons of DEF are left in the tank:



I add 2.5-3 gallons when this message is displayed, an at the next start, the "exhaust fluid level OK" message is displayed.

Wintersun - Why would the oil be cleaner ? DEF is injected into the exhaust after it has exited the combustion process.

Tim

VinnyP wrote:
Problem Solved! All of you, and my wife, were right. I added another 2 gallons of DEF and 30 seconds later the doomsday messages stopped. Now if I could only get my wife to stop saying "I told you so." Thanks for all the input.
Happy Trails!

If you figure that out please let us know ;)

I love DW because along with everything else she keeps me humble!

Huntindog wrote:
I'm glad my GM doesn't work like that. I have been waiting for the message and then adding 2.5 gallons. I don't want to fill it as the high heat here in AZ rapidly accelerates the DEF degradation.
I don't drive it enough to use it up all that fast sometimes. DEF that has gone bad in the tank pretty much means a tow truck to the dealer. Not a warranty item either.

I'm glad my Ford doesn't have the DEF Poor Quality problems. :W

Doctor DEF - Thank you for the tip. I have looked at the 'exhaust fluid' message but I've only ever gotten the message that the level was 'OK'. So thanks for letting me know about that. I'll start looking at it weekly. You're right, this should solve the problem

Tim

GoPackGo wrote:
Wintersun - Why would the oil be cleaner ? DEF is injected into the exhaust after it has exited the combustion process.

Tim

Think with DEF there is less or no Exhaust Gas Recycling (EGR) which causes the soot in the oil.

And DEF should increase the mileage, but since more soot is now collected in the particulate filter, that needs to be regenerated more, which reduces mileage.

It's complicated ...

I have a 2012 6.7 and don't care for the gauge at all. Above or under in a 5 gallon tank leaves some leeway and as mentioned you don't want to overfill as I don't put many kilometers on come September and with our climate here the def freezing could cause tank fracture. I know the heater works but not much help on my short commute.
I think the ram has an actual gauge measuring full to empty???
Love the truck but this is only complaint. Minor.