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DEF usage on 2020 HD models


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Prior to them performing this reprogram, my DEF sensor wouldn’t recognize that I added more fluid for anywhere from 100-300 miles after topping off. Also, I was going through a gallon of DEF every 300-400 miles. Now, the sensor immediately recognizes when I add fluid and I’ve seen closer to 700-800 miles per gallon over the last 4,000 miles.

I don’t trust it so I carry DEF fluid with me in my truck on long hauls if I know I want me passing truck stops with DEF pumps.

Hope it works for you! Let me know if you learn anything new and different that helps!


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As much as I wish I had some news here, my dealer is telling me that 7 ½ gallons of DEF under load for 2000 miles is about right... Sad that now we're going to have to start toting around DEF on trips. 

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I started keeping track of it on mine and now have one data point.  Over the last 1664 miles it used 4.2 gallons for 397 MPG of DEF.  The diesel MPG was 12.8 overall, most of that was towing the 9k RV.  

 

I just set up an alternate vehicle on fuelly and get the DEF at the truck lanes in the truck stops.   

 

My truck had some DEF system recall done back in June when it threw a code. 

Edited by XY74
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@XY74: I'm in the same range as you, towing my Airstream 8.5-9K lbs. So looks like there's a couple fo data points we have.. Yours and mine. 

 

You're getting nearly 400 Miles per gallon of DEF, mine is only about 260 miles per gallon of DEF. I'm really hoping that it gets better. However, my usage was in the mountains, which I'm not sure has anything really to do with it, but apparently can affect things.  ¯\_(ツ)_/¯

 

-Wayne

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  • 2 weeks later...
On ‎10‎/‎10‎/‎2020 at 3:10 PM, XY74 said:

I started keeping track of it on mine and now have one data point.  Over the last 1664 miles it used 4.2 gallons for 397 MPG of DEF.  The diesel MPG was 12.8 overall, most of that was towing the 9k RV.  

 

I just set up an alternate vehicle on fuelly and get the DEF at the truck lanes in the truck stops.   

 

My truck had some DEF system recall done back in June when it threw a code. 

That is exactly the same amount of DEF usage I got on a recent hunting trip towing a 10k trailer and a quad on the truck. 

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  • 2 weeks later...

I tow a 28ft cargo gooseneck, 12k-15k pounds everyday, trailer never leaves the truck.  I fill the tank weekly as I can't go two weeks before I run out.  I get approx 1800 miles a tank, did the dealer update, just screwed up the gauge.  It shows higher then what is really in the tank, since I fill it weekly and my trips go along generally the same route its easy to gauge consumption.  

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  • 2 weeks later...
On 10/9/2020 at 2:15 AM, Wbrisett said:

As much as I wish I had some news here, my dealer is telling me that 7 ½ gallons of DEF under load for 2000 miles is about right... Sad that now we're going to have to start toting around DEF on trips. 

Just had mine reset yesterday at the dealer, they new it was a thing when I went in so that was good. I had reset trip B last time I filled the DEF tank and had driver about 1200 miles, no towing, just back and forth to work. After reset gage went from full, to down one square. I needed fuel anyway so while there I filled the DEF. It took 1.20 gallons....So I called the dealer to see if they added any, and he said no. I said I just topped it off and after 1200 miles I only needed 1.2 gallons. My dealer said that’s about what their seeing if your not under heavy load all the time. He also said a tank, 7.5 gallons in about average if towing all the time every 5000 miles. Just FYI. 
 

Aldo just do Google searches when traveling. I have found 3 stations near me for day to day that have DEF pumps to fill at when it comes, super convenient.

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On 1/2/2021 at 1:27 AM, Camstyn said:

I’ve gone about 2500 miles and my gauge says half full, no towing.

I think it has to do with the DEF you use.  I did fuel pump def for my first fill up and went about 3800 miles.  I filled up with the more MPG efficient "green" version of PEAK and it started throwing codes left and right. "DEF quality" "DEF levels" etc all thrown after started using the Green PEAK stuff.

 

I'm going back to the pump after I get through this batch of DEF in my tank.  I will say, I'm noticing that my Regens are fewer and further between (800 miles, regardless of Soot Level) as opposed to the previous 450-600 miles with the Green PEAK DEF fluid -- which is why they're able to advertise the higher MPG.

Edited by Schmidty
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In my 2018 I've been getting a 750 miles Remaining DEF thingie message but it's popped up twice in the last 3 weeks.. No towing, just highway/city driving.  Then I check the DIC and it says level ok. 

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  • 1 month later...

DEF is DEF there isn't a premium grade.  Get it from the pumps at the diesel islands at truck stops - it's a lot cheaper and guaranteed fresh.  Truck stops use a lot of it and it won't have been setting in a warehouse for months before you get it.

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