Little or No DEF Usage. Concern?
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Tuned
Joined: Dec 2007
Posts: 354
Likes: 0
Little or No DEF Usage. Concern?
Have put 1600 miles on my F350 since I last check the DEF. I could only drizzle in 16/100 of a gallon so appears I am using little or no DEF. That much could have even evaporated in the summer heat.
Should I be concerned?
If I understand correctly, the DEF should continuously be sprayed into the exhaust to reduce NOX and to keep the EPA happy. I do have regenerations as frequently as every 70 miles when some in town driving is involved and about every 175 miles on mostly highway driving. If my knowledge is correct, the DEF is totally independent of regeneration to burn off the soot in the Diesel Particulate Filter.
It appears I may have a failed DEF pump or sensor of sorts. Although I am not getting any codes on the command center display or thankfully, no Check Engine Light, I presume the dealer should be able to hook the truck up to diagnostics and determine of the DEF pump or sensor associated with it is bad.
Any else seeing this?
Note: I do get the brief 2 second message notifying of the truck going into Regen, but like everyone else, mine does not stay on the way it did with my 2008.
Should I be concerned?
If I understand correctly, the DEF should continuously be sprayed into the exhaust to reduce NOX and to keep the EPA happy. I do have regenerations as frequently as every 70 miles when some in town driving is involved and about every 175 miles on mostly highway driving. If my knowledge is correct, the DEF is totally independent of regeneration to burn off the soot in the Diesel Particulate Filter.
It appears I may have a failed DEF pump or sensor of sorts. Although I am not getting any codes on the command center display or thankfully, no Check Engine Light, I presume the dealer should be able to hook the truck up to diagnostics and determine of the DEF pump or sensor associated with it is bad.
Any else seeing this?
Note: I do get the brief 2 second message notifying of the truck going into Regen, but like everyone else, mine does not stay on the way it did with my 2008.
Post Fiend
Joined: Apr 2004
Posts: 5,158
Likes: 35
From: North of Salt Lake City
The frequent regens and lack of DEF usage are indicators of your driving style. Sounds like you use your truck in mostly short trips and no trailer. That would cause a relatively quick build up of soot in the DPF requiring frequent active regens. Since the exhaust is not really heating up, the truck is not able to utilize passive regens. Also, DEF is only injected into the exhaust when exhaust temps are very high. It is only in this environment that NOx is created so therefore the NOx sensor is not detecting any. No NOx, no DEF being used. Sounds like the truck is doing what it should.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
I agree with Epic on this one.
Remember that your truck has a sensor for NOx in the exhaust system. If you had un-treated NOx passing through the system the sensor would allow the computer to detect this. If the computer tried to increase the DEF dosage and saw no reduction of NOx, as would happen if you had a DEF pump failure, you would see a check engine light.
Remember that the EPA required these trucks to be nearly foolproof with how they treat the exhaust gasses. There are many redundant checks to ensure that the system is working properly, if you have no CEL on there's nothing to worry about.
Remember that your truck has a sensor for NOx in the exhaust system. If you had un-treated NOx passing through the system the sensor would allow the computer to detect this. If the computer tried to increase the DEF dosage and saw no reduction of NOx, as would happen if you had a DEF pump failure, you would see a check engine light.
Remember that the EPA required these trucks to be nearly foolproof with how they treat the exhaust gasses. There are many redundant checks to ensure that the system is working properly, if you have no CEL on there's nothing to worry about.
Cargo Master
Joined: Aug 2007
Posts: 2,862
Likes: 0
From: Kentwood, Louisiana
If your not using DEF, I would say that before long you will see a warning that you have contaminated exhaust fluid & you will restricted to 55 per hour in 200 miles, this has been happening to me for a while & the warning always went away before the 200 miles occured. One of the four dealers I went to pulled up a bulletin that indicated loose wires on some sensor. Now the light stayed on and sure enough the struck is restricted to 55 miles per hour, but the computer tells me the reservoir is full. I have talked to serveral service peeps & they have no clue to the problem. So,Tuesday I'm taking mine to leave at the shop in McComb, they will be able to find the problem hopefully, I'm hoping it will be a simple fix.
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Tuned
Joined: Dec 2007
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Edit:
Pulling out the technical documents on the DEF system, it get sprayed into the exhaust stream after the Diesel Particulate Filter.
Pulling out the technical documents on the DEF system, it get sprayed into the exhaust stream after the Diesel Particulate Filter.
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Thread Starter
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Tuned
Joined: Dec 2007
Posts: 354
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5900 Miles: Still no DEF usage since I had my DEF tank topped off the week after delivery.
I do not regularly tow, but do use my truck most weekend here in the NC Mountains.
Either I have a failed sensor, failed DEF pump or crimped DEF line that has been reported on some trucks. Having the dealer sweep for codes next time I am in.
I do not regularly tow, but do use my truck most weekend here in the NC Mountains.
Either I have a failed sensor, failed DEF pump or crimped DEF line that has been reported on some trucks. Having the dealer sweep for codes next time I am in.
Postmaster
Joined: Aug 2011
Posts: 4,637
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From: Roll Tide, Roll
they dont have a quage like a fuel guage. level okay, below half or a warning at 800 miles. if you dont tow, chances are your using very little. if in doubt add some and see.about $12 at o reiley for 2.5 gallon jug. even walmart has it.
Tuned
Joined: Feb 2011
Posts: 414
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From: Indian Trail, NC
I have just over 6000 miles on mine and have used almost 5 gallons of DEF. Just before our 2000 mile trip in July, I had the oil changed and DEF top off. The truck had 3k on it at that point. It took about 2.5 gallons then. Now at 6000 miles, I checked the message center again and DEF was under 1/2 full again. So, in 6k miles, I have used about 5 gallons of DEF. Over 3000 of those miles are towing.
Cargo Master
Joined: Jul 2008
Posts: 2,576
Likes: 56
Around 4000 miles I added 2.5 gal after the 1/2 tank message (in the menu) and have close to 7000 miles now - no 1/2 tank message yet. I haven't pulled any trailers yet, but I have run a couple thousand miles with a loaded bed.