# DEF tank level vs range warnings



## KyleB (Mar 12, 2017)

'17 CTD ~11k mi
Currently the DIC tells me I have 18% in the DEF tank. The DEF countdown warning I started getting each time I start the car tells me I have 260 miles range. These don't agree with each other. 18% of a tank of DEF should take me WAY farther than 260 miles. 
I've put a jug of DEF in my trunk so I can fill it any time. I like to let it run down so what is in there is as fresh as possible. 

Thoughts?


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## IndyDiesel (May 24, 2015)

I think playing games with the computer may not be worth not just adding the def. I have gen 1 and I drive a lot but I haven’t had any issues with DEF quality and the gen 1 has a larger capacity of DEF and seems to be programmed to go much longer, I think with my driving I can go 15k miles on a full tank of DEF. 

I would just fill your DEF tank and not worry about it.


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## MRO1791 (Sep 2, 2016)

KyleB said:


> '17 CTD ~11k mi
> Currently the DIC tells me I have 18% in the DEF tank. The DEF countdown warning I started getting each time I start the car tells me I have 260 miles range. These don't agree with each other. 18% of a tank of DEF should take me WAY farther than 260 miles.
> I've put a jug of DEF in my trunk so I can fill it any time. I like to let it run down so what is in there is as fresh as possible.
> 
> Thoughts?


There are many assumptions any range estimate has to include as part of the caculation. How you drive can make a big difference on how much DEF is used, likely it will go beyond the estimate, worst case, probably not. I concur with indydiesel, just add the DEF and don't worry about it. Neither of my 2 Gen 1 cars have had DEF quality issues. I'm also in a mild climate. Hot is the death of DEF shelf life and quality. 

Sent from my Moto G (4) using Tapatalk


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## johnmo (Mar 2, 2017)

The jug of DEF in your trunk isn't getting any fresher while you drive around waiting to put it in...

The 260 miles of range is probably what you have left before it hits 10% and it starts limiting speeds. I let mine get almost that low this month and the countdown coincided with hitting 10% remaining.


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## boraz (Aug 29, 2013)

youre overthinking it

"fresh def" is not a thing.


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## KyleB (Mar 12, 2017)

johnmo said:


> The jug of DEF in your trunk isn't getting any fresher while you drive around waiting to put it in...


No, but the old DEF is getting used up making the blend I create when adding the new, newer. 

Agreed that in Fall/Winter temperatures I'm probably overthinking it. I was mostly confused about why it would claim 18% of a tank of DEF would only take me 260 miles. Even if it's claiming 260 miles until 10% and more dire warnings, that's only 3250 mi per tank of DEF. Even that feels on the low side. 

In any case, I added some and all is well.


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