DEF Tank not reading correct
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Lead Driver
Joined: Nov 2005
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From: Kaysville Utah
DEF Tank not reading correct
I usually check my DEF on a regular basis and when ever it gets below 1/2 full I add a jug. Two days ago, I checked and it was showing DEF OK. Today it poped up and said 800 miles to empty. I was suprised, But bought a 2.5 gallon jug and tried to add it. It took 3/4 of the jug and overflowed. So it was full. Command center is still giving me the countdown of 7xx miles left in DEF. Guess I need to make a trip into Dealer.
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The same thing just happened to me. Just had the oil changed at 22,000 plus miles. So had them change the fuel filters too. They topped off the DEF and left a partial jug in the bed. Washed the truck for free. I was pleased. Then a couple of days ago it showed the 800 mile warning. Didn't think much of it, figured it was a fluke. But it kept counting down. So I concluded the guys at the shop put the jug in the back and forgot to use it. Bought 2.5 gallons at the parts store to add to the partial jug I had left at the house. It took about a gallon. DEF tank is completely full, and still counting down. Guess I'll talk to the dealer too.
Senior User
Joined: Jun 2009
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Painted Horse, I assume with all the towing you do it is fairly common that you have to put in a jug or two between oil changes? I recently went to top the DEF off because it had been showing under 1/2 a tank for a few days and it took 3/4 of the jug and then spit DEF out all over the place. Rather frustrating as I'm really careful to make sure the spout is tight and everything is aligned.
I wonder how the gauge is set up in the tank because on the DashDaq it show DEF level but it never has gone above 3.21 gal, even when it is full, I think it's a 5 gal tank.
I wonder how the gauge is set up in the tank because on the DashDaq it show DEF level but it never has gone above 3.21 gal, even when it is full, I think it's a 5 gal tank.
Mountain Pass
Joined: Mar 2011
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Mine did this too when I was using the truck to haul continuously and in the tow/haul mode. I added about 2 gallons and it overflowed, so it had a hell of a lot more than 800 miles in it. After using the truck normally for a couple days the 800 mile warning went away on its own and went back to saying OK. I think the tow/haul accelerates the reading on the dash as it assumes you are going to be using more. I say give it time.
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I have been towing a lot so when I reached 4100 miles I got the message 800 miles till empty. So, thinking that I would get an oil change at around 5000, I added a gallon of DEF to tide me over till the oil change. The gallon would not register, and it kept counting down. I called a dealer service department and was told that in order for the system to reset, you have to fill the tank. Once I did that, it reset.
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Well, my tank was full. And it continued counting down - it was under 500 miles when I took it to the dealer. Dealer reset the DEF system and then informed me the software upgrade was indicated for my truck. So I told them to flash it. It is now up to date and the DEF system is happy. No info on why the false indication. But it's gone for now...
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Lead Driver
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I think it shows DEF in percentage but I only enabled that PID for about 15 seconds before I became bored with it.
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Lead Driver
Joined: Nov 2005
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From: Kaysville Utah
The DEF PID shows prettym much the same thing the command console does, Full, Half full, Almost empty. It can only show what the sensor read, Since the DEF tank has very limited capacity sensor, the PID has very limited imput to report.
I under stand that the 800 mile readings won't clear up unless you fill above a certain point. My concern ( and apparently several others above) is that the 800 mile reading came while the tank was 2/3rds full. It had not even reached the 1/2 full mark and it started the miles to empty count down. With 800 miles to empty, I should have had no problem dumping in 2.5 gallons. so it pisses me off when it's too full to accept 2 gallons and have DEF spilling.
My system did reset today and it shows DEF as OK, But it took 10-12 restarts of the engine before it cleared itself. Didn't have time to worry about it today or tomorrow. But later in the week, I'll call my service advisor and ask what's up. With folks reporting losses in mpg, I'm not too interested in the latest TSB. My tranny works OK, So leave well enough alone.
I under stand that the 800 mile readings won't clear up unless you fill above a certain point. My concern ( and apparently several others above) is that the 800 mile reading came while the tank was 2/3rds full. It had not even reached the 1/2 full mark and it started the miles to empty count down. With 800 miles to empty, I should have had no problem dumping in 2.5 gallons. so it pisses me off when it's too full to accept 2 gallons and have DEF spilling.
My system did reset today and it shows DEF as OK, But it took 10-12 restarts of the engine before it cleared itself. Didn't have time to worry about it today or tomorrow. But later in the week, I'll call my service advisor and ask what's up. With folks reporting losses in mpg, I'm not too interested in the latest TSB. My tranny works OK, So leave well enough alone.
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I was a bit leery of the new flash too, for the same reason. But my fuel economy actually seems to have improved a bit. And now I don't have to push the button to illuminate the gear numbers every time I restart the vehicle. 
Lead Driver
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Yea, no need for an update if you're issue free but you know that's what they'll want to do.
I obviously remembered incorrectly about that sensor and PID.
I haven't touched my truck in almost a week so I'm losing it anyways...lol.
I obviously remembered incorrectly about that sensor and PID.
I haven't touched my truck in almost a week so I'm losing it anyways...lol.
Junior User
Joined: Sep 2010
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In 2010 mine said 600 miles to empty, then it said empty about 2 hours later. I don't drive that fast. I managed to get it refilled on a Sunday right before Christmas. Then it said empty in "1189" miles, specifically, for about 2 months. Looked like someone had dropped an old calculator. It was so obviously wrong. My dealer said there was no issue. I learned to carry some DEF with me. And to ignore dealers. I wonder if there is a new flash since then.
Postmaster
Joined: Sep 2006
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From: Maryland
A lot of the early build trucks had this problem. For the most part, everybody I know that had this problem had it fixed by the latest flash. My truck was built in September 2010 and so far has acted fairly normal with the exception of getting hung up on the same miles to empty for a few days one time.
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Well, my official commentary on the flash update is, bravo! Noticeably more torque and significantly better fuel economy - 2 mpg. It's almost like driving a new truck. I bought it in late September last year. I love my truck!