I have a 2023 F-350 Super Duty. On a recent trip I kept getting a 499 to empty message and to refill DEF soon. I had to do this 4 times from Tennessee to Florida and back. Average 2 to 3 gallons each time I put DEF in the truck. Is there a "known" bug in the DEF system. This 2023 has NEVER got as good DEF mileage as my 2017 did. I don't know if the gauge is faulty or if there is some component that needs replaced. I plan to have Ford look into it but I was hoping there might be other information I could use regarding the DEF system. I also had something replaced recently regarding DEF but I can't remember exactly what that was. It was a part that had to be ordered.

 

Typically engine loading determines how fast you go through DEF. Two things really create loading on an engine - speed, and actually hauling a load, either in the bed or on a trailer. So my first question would be, were you towing anything? And my second question would be how fast were you driving? Because at 75-78 mph mine doesn't use much DEF (though it does use more than my standard work commute), but towing at 65 mph burns through it quite a bit quicker. If you are running 80+ or towing, you're going to burn through it quite a bit quicker.

This isn't saying you don't have a problem - you might, your injector might be stuck open.

 

I was towing our horse trailer but no horses. I had bicycles and dogs and cats My Setup in the pic attached from this trip. I try to travel between speed limit to 5 mph over but now and then you want to get away from an idiot on the road and I have reached higher speeds doing that I'm trying to reduce my lead-foot. I am a work in progress. I'm good so long as I can use Cruise control but when it's raining you can't use it. So I tend to drift up more than I'd like.

However, I always had a lead foot in my 2017 and my GVWR trailer at that time was 18K. It was a full 4K heavier than this trailer. You could FEEL the difference between the two trailers even with my 2017. Still this truck guzzles DEF. I hate that. It's a real pain and it NEVER FAILS that people will pull up to the ONLY place at Buccees you can get DEF and Diesel and go lounge in the store for half hour or more. One guy this time actually came back to his truck and moved out of my way (but there was another in front of him) and then he proceeded to the other side of the pump to fuel up. He then sat there and ate lunch blocking the diesel and DEF pumps on that side. It is astonishing how RUDE people are these days. ..

 

I saw your other post too. What does your def gauge read when you get the 499 message? When you put def in are you filling it to full? The 2023 and up use a lot more def than prior MY's but thats a good thing because the newer engine are routing way less egr back through the engine.

We recently made a 500 mile trip towing our 16k 5th wheel from Michigan to Kentucky, and takes about a 1/4 to 1/3 tank of def. Thats 2-3 gallons. If you are not filling your def tank to 100% then thats the source of your frustration. Same with running your fuel tank down to E before filling and getting stranded along I75.

 

I don't know what the gauge reads. I have never looked because I can't remember how to find it..lol. But Each time I got that message and filled the def it was less than 3 gallons. Yet I think it used over 7 or 8 gallons on the entire trip ( I need to add up the reciepts). It's a 690 mile trip one way (Whitesburg Tennessee to Brookesville, Florida). My other truck would not have used half of that. I always fill it to full best I can. A couple of times it ran over too because the nozzle didn't stop the flow. Now I don't really trust it to do that. But I get pretty close to full. Nice rig you have

 

Yeah my 2020 would do that. Suggest filling it up before taking off next time and topping off before the 500 warning as it wont register well when towing. Kinda ridiculous.

Glad they are changing the DEF fault warnings and limp mode misc with the current admin/epa.

 

But the problem is I get the 499 warning after a single fill up! It is ridiculous. That is why I ended up putting DEF in 4 times to get rid of the stupid message and pop up warnings - another thing I dislike about this truck. Too much idiot-proofing that is super annoying.

 

Will those changes be able to help me via download or something? That would be wonderful!

 

There are some articles on it here on this site with more details.

 

I didn't mention it, but the DEF tank percentage full is in the diesel gauge detail screen. Would be interesting to see what it says when you get the 499 message. If it is in the 80-90% range, then it sounds like you have a issue that Ford should address. If the gauge is low like 20% then you aren't filling it fully.

 

So my truck is currently at the dealership where they are replacing the entire def tank. I had the exact same issue as the op. I would start with a full def tank and fuel tank and then start getting the warning, but when I would refill the def tank to the top, it would only take about 1.5 gallons.

Previous to my last 1,000 mile trip, where I had to carry 5 gallons of def in the bed, because I was paranoid I wouldn't find a fuel stop with it at the pump, every time I would fill the def tank full, the truck would report around 85% full. At some point, it just quit reading the def levels correctly.

 

I'm sorry to say this, but FORD will do nothing about this issue. They may replace your tank, but the issue will continue. I had the same issue. I went so far as to tow with one tank of fuel, set the 499 to empty message, then run the next tank of fuel empty. Once the 499 to empty message is set, the truck will ignore the tank level and go into limp mode when to mileage to empty reads zero. My truck had 3 gallons of DEF left in the tank. The dealer even confirmed it. It is all software issues and FORD got a Field Engineer involved, but he was not a software person so nothing was done. Ultimately, the trucks are using TO much DEF. The exhaust can not vaporize it all. When I removed me exhaust, there were golf ball size chunks of DEF crystalized in the pipe. I sent those pictures to FORD and still they did nothing about it. I have since solved the problem and hope to never go back.

 

I am going to note the levels next time. It would be good to have a record of that anyway to give to the service people. I put as much in as I can without it overflowing by sound so I don't "think" that is the issue but not 100%. I'm afraid to trust the auto shut off since last time it did not work and I had a mess. Thanks.

 

I have been looking for my ticket but haven't found it yet. I believe they replaced my DEF tank last time I was having issues too. Apparently it needs another one! I should carry extra DEF too. I normally get to a station soon after the first warning blip comes up but it can be a pain around town and normal driving to find it at the pump. I have to go to a truck stop to get it at the pump and it's a lot cheaper there. Still, wouldn't hurt to have a jug of it onboard.

 

HOW did you solve the problem? That sounds about right as to using more DEF. I know this truck uses at least half again as much as my 17 and maybe more than that!