In the "Settings" menu, under "DTE Calculation", it appears there is an error in programming. There are two options to select: "Normal" and "Towing".
When towing is selected, the DTE number goes up. When "Normal" is selected, the DTE value goes down. For example: this evening on a full tank, the DTE number was 780 with towing selected. When I changed it to normal, the number went down to 550. This seems backwards. Ford, care to comment??
2015 F-150 XLT FX4 3.5L EcoBoost

 

Subscribed to see if someone from Ford answers.

 

I'll have to check mine!

 

Apparently this issue is isolated to a particular model. My 2.7L work truck functions as you'd expect. Ford this is a modest safety issue. I just took a 3500 mile vacation through the desert southwest towing a trailer in 100+ degree weather and there are many spots where it's 100 miles or more between gas stations and a DTE calculation that gives you a bigger number when set to towing could help create an out of fuel situation.

 

DTE is just a estimate and should not be used as fact, I would suggest if your concerned about distance between fueling stations then maybe a spare can of gas should be taken with you on your trip

 

That's not the point. The issue is that there is a problem and Ford needs to address it.

 

Have to disagree, my truck displays properly. This just may need a reflash of the software by the dealer. I would be interested in how may 3.5's are having this problem.

 

I'm not saying it is a problem with all the trucks. But it is at least a problem with His/Her's truck, so Ford needs to fix it.

 

Have to admit that I don't pay that much attention to it. However, I do notice that the DTE calculation adjusts dynamically to whatever your instantaneous mileage happens to be. When I'm going up the mountain, my DTE goes down quite a bit, but when I'm going down the mountain, the DTE magically goes back up. My instantaneous mileage going down the mountain is nearly 30 MPG.

 

In the interim, I'd suggest hand calculating your fuel economy for a while towing and empty just so you can become more familiar with your truck.

 

I'd use something like gasbuddy app on your phone if you have one to help out or plan a trip accordingly. On any vehicle equipped with a DTE, I never pay any attention to them since they are inaccurate. Doesn't matter if its new and improved, last thing I'd want to do is trust a computer for doing the math for mileage. Rather just fill up when you can on a trip, especially while towing. I haven't seen any Ford reps on here since the Q&A session a while back, do they even frequent the forum anymore? I agree with Tim and do it by hand until something gets figured out.

 

I guess there's a remote possibility that your Tow/Haul mileage mileage is better than your normal mileage. In that case the DTE, which probably uses the average MPG for that driving mode, would show a longer distance for T/H than normal.

When you switch over to T/H in Settings does the average MPG change?

 

Took my truck on a drive today and I played with the DTE calculation. But, I'm confused with the results:

• The DTE showed 690 miles on Normal, but it went to 654 miles when I switched to Tow/Haul - and when I immediately switched back to Normal the DTE stayed at 654.
• About 6 miles later the DTE showed 648 miles on Normal, but went up to 677 when I switched to T/H

Oddly enough, I didn't drive in T/H at all, so the calculated MPG for T/H couldn't have changed between those tests. So, I don't have an explanation as to why the DTE changes.

Also, I can't find anything in the owner's manual that explains how the DTE calculation is done, nor what the difference is between Normal and T/H for DTE. I downloaded the manual as a pdf and searched it, but the few hits for "DTE" didn't explain whatsoever about how it is done. But, if anyone finds it, please let me know.

 

Curious to know, with stock tires is the speedometer even dead on? I know that at least in the early 2000s and previous Ford allowed a +/- 3mph difference between the speedometer and tire size reading. I know on my truck running stock 255/70/16 I have to drive at 58mph on the speedo to be going 55. But with 265/75/16 its dead nuts on the money. I know its a 16 year gap but it should be relevant.

 

Mine is dead on when checking with GPS. And that's with the stock 20" tires and wheels.