I had a problem recently with my DEF that's different than the more common problems I've read on here. 2-3 weeks ago I got the 500 mile DEF range warning on my dash, but I hadn't gotten a 1/2 full warning before that. I decided to let it clock down until it got below 200 before I put a couple jugs of DEF in it. During the range count down, I noticed the DEF level reported by Torque on my tablet had said 0.8gallons. Then I noticed the next day it said 3.0 gallons, and a couple days later it dropped back to 0.8. Then one last time it popped back up to 3.0 and stayed that way for the rest of the time until the warning was down to 183 miles left. I bought two jugs of DEF, and the next morning I set out to top off the tank. Using my Ford spout, it stopped filling before I even finished putting in the first 2.5 gallons! I estimate I got about 2 gallons added before the tank was full, but it should have taken nearly 5 gallons if it truly had on 183 miles left! The reading on my tablet still said 3.0 gallons of DEF, and I continued getting the DEF range warning counting down for probably 6 or 7 drive cycles. The last reading was 149 miles, and at the next startup this morning I didn't get the warning anymore. The reading on the tablet went up to 3.1 gallons after the warning stopped, which is the highest it ever reads using Torque.

What I don't like is the varying DEF tank level (0.8 and 3.0), and the truck telling me I have 500 miles of range all the way down to 183 miles when the truck has only used 2 gallons of DEF since the last fill-up. I did leave a message on my service writer's phone last Thursday, and when he calls me back I plan on asking him to document this problem in my truck's record. I am still covered under and extended warranty until July, and I want to be sure this problem is covered if it doesn't surface again until after July.

I feel like this is an indication that the tank level sensors are intermittently reporting a wrong DEF level. Thoughts?

 

The DEF tank on the 2011-2016 trucks has a non-linear measurement system. There are 4 probes in the sensor that are used to measure the DEF levels. There is one probe that is the common probe for the other 3 probes. The probes send signals to the PCM to compute the tank levels and when to give the 500 mile count down. So, you can not go by Torque or any other app/programmer/monitor and get any kind of accurate level indication in gallons/liters or parts of gallons/liters left in the DEF tank.

 

I conquer, when Torque Pro says the tank is full it reads 3.1 gallons and it will not move off that number until the DEF drops to the less than half mark. When I recieved the 500mi to empty message Torque Pro was indicating .8 gallons.

I can say with confidence your truck was confused like they do from time to time.

Have a look at my thread here on the same issue with the same Torque Pro readings a you described.
https://www.ford-trucks.com/forums/1...ge-500-mi.html

 

Yes it was confused. Now why the false count down readings when it appears that you did not add a partial fill up.

 

Yup, I'm familiar with the operation, but thanks for posting anyways Larry. I use the numbers reported by Torque as trend and general indications like dirthawg confirmed. The jumping from a near empty number, 0.8, up to an almost full number and back again wasn't right, and the truck telling me to put in some DEF or I was going into limp mode in less than 200 miles was a complete lie. Since the system seems to have reset, I'll just have to wait and see.

 

Thanks for the confirmation dirthawg. I tend to see 3.1, then one point something when it's around half full, and then 0.8 when it goes into the 500 mile countdown. I remember your thread, and I remember recommending you wait a little longer. The difference with mine is I watched mine tick all the way down from 500 to 183 miles (317 miles of driving) with a tank that had over 3 gallons in it as it turned out. Dang thing should have reset, but it didn't until I put in a couple gallons and drove another 34 miles. That Torque level jumping around doesn't make sense either.



Completely agree Senix. I don't do partial fill-ups. I wait until I'm somewhere in the 500 mile countdown to add DEF, and if I'm not going anywhere of distance soon, then I wait to get under 200 miles. Clearly confused this time with the up and down DEF levels in Torque, plus, the warning for over 300 miles when there was still about 3 gallons of DEF in the tank. At this point, the warning cleared, and I'll just have to wait and see what happens. It may just take a while because this time of year I don't really do any towing. So the DEF consumption will be slow.

Thank you both for responding