User Tag List

Page 1 of 3 123 LastLast
Results 1 to 10 of 27

Thread: DEF Fluid Warning

  1. #1
    Site Sponsor
    Join Date
    Jul 2020
    Posts
    1
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    DEF Fluid Warning

    We are towing our Grand Design 5th wheel with a 2020 Chevy Silverado 2500 Heavy Duty Diesel and we received a DEF Fluid warning for 1000 miles. When we check the level it is at 3/4 full. The mileage does not seem correct because over the winter we would fill up with DEF Fluid and it would say 600 - now that we are towing we fill up with DEF fluid it says 360. We are thinking it is because we use more DEF fluid when towing so it throws the formula off and gives a warning. BUT if the truck is going to regulate speed because of thinks it is low we are out of luck. How do we move forward, the truck thinks it is low. The fluid is in there. The system is going to take over. Itís like the brain doesnít the bladder if full.

  2. #2
    Site Team D2Reid's Avatar
    Join Date
    Dec 2016
    Location
    Somewhere, USA
    Posts
    2,494
    Blog Entries
    3
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)
    Welcome to the forum. If it were me I would take pictures of the dash and record the mileage and type of driving then take it to a dealer, sounds like a control module problem what should be covered under warranty.
    Dallas
    2017 Momentum 376TH, 2019 Ford F450, Dual Rear Wheel, 4x4, diesel.
    2015 Harley-Davidson Street, XG750

  3. #3
    Seasoned Camper That 1 Ron's Avatar
    Join Date
    May 2020
    Location
    NW NM
    Posts
    201
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by D2Reid View Post
    Welcome to the forum. If it were me I would take pictures of the dash and record the mileage and type of driving then take it to a dealer, sounds like a control module problem what should be covered under warranty.
    I agree with this. Take pictures of messages on the dash and find a gm dealership/service center. My guess is either a sensor or wiring harness issue but it just might need a re-flash. My father-in-law just went through something similar on his 2019 D-max which turned out to be a sensor in the DEF tank.
    2020 Grand Design Imagine 2400BH
    2017 Toyota Tundra TRD Pro Double cab

  4. #4
    Seasoned Camper
    Join Date
    Jun 2019
    Location
    Vancouver, WA
    Posts
    233
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    FYI

    DEF and mpg should be fairly equal. I get @4000 miles w/o towing at 19mpg. When towing I get 10mpg and @2000 miles on DEF.
    Bob and Cheryl, Puka the doodle
    2018 Ram 2500 Crew,Diesel,4x4
    2016 Reflection 27RL
    2012 Palomino 6.5 camper

  5. #5
    Site Team traveldawg's Avatar
    Join Date
    Aug 2017
    Location
    Florida Space Coast
    Posts
    1,739
    Blog Entries
    1
    Mentioned
    34 Post(s)
    Tagged
    0 Thread(s)
    Ford guy here..... When not towing it seems I use less DEF than when towing. No scientific proof or logging. But it seems that way.

    And, not that DEF is involved, but the regens come at shorter distance intervals when towing. When not towing it seems pretty consistent at about 497 miles (and the percent soot gauge shows 100% too) and the region brings the soot level down to about 12%.

    When towing it might be 300 miles or so when a regen occurs and also when the soot gauge shows 100%. But it only burns down to about 27%. I'm trying to figure out if the regen burn is a timed event or if it senses soot levels.

    So I figure if regens are more frequent when towing that I must be sooting up soon which means something is working harder and maybe using more DEF.
    Larry
    2018 F350 SRW SB - AirLift 5000 w/Wireless One; ForScan; 37gal RDS Fuel Tank; Demco Hikacker
    2019 310GK-R - Sailuns; MorRyde SRE4000; Disc Brakes (StopYourTrailer.com); Electric Cord Reel


  6. #6
    Site Sponsor
    Join Date
    Apr 2017
    Location
    Fort Collins, Colorado
    Posts
    1,047
    Mentioned
    18 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by traveldawg View Post
    I'm trying to figure out if the regen burn is a timed event or if it senses soot levels.

    So I figure if regens are more frequent when towing that I must be sooting up soon which means something is working harder and maybe using more DEF.
    Both, a regen is triggered by either the soot level (measured as pressure differential across the DPF - Diesel Particulate Filter (a ceramic disk with many very small holes through it)) exceeding a threshold or roughly 500 miles. Whichever comes first. Oh, and certain engine parameters have to be met (engine warmed up, minimum speed, etc) to start the regen.

    In the current Fords (I do not know about other brands, but probably applies) there are two types of "regen" passive and active. Passive happens under heavy loads (and normal driving?) when the exhaust temp is high enough to burn off the soot. This typically does not reduce the soot load, but rather slows down the accumulation of soot. The higher and longer the load (i.e. towing ) the more effective this is. The other type is what we all know and love (insert your favorite emoji here), and is called active regeneration. This is where they dump raw (unburned) fuel into the exhaust pipe and it burns in the pipe down stream of the engine greatly increasing the temperature at the DPF and thus burning the soot/oil into a fine ash.

    Towing is a balancing act between burring more fuel and thus generating more soot and running at a higher exhaust temperature thus burning off or at least slowing the accumulation of soot in the DPF.

    DEF (Diesel Exhaust Fluid) is also an emission control approach but it is aimed at reducing NOx (Nitrous Oxide) emissions, this is completely separate from soot. However, they are both effected by engine temperature (i.e. how heavy of a load). Higher temp/load tends to reduce the soot but increase the NOx emissions. I notice I get longer time between regens, but use much more (3x~4x) DEF when towing compared to unloaded driving. That is just my experience.

    Hope that helps some

    Chris
    Last edited by CoChris; 04-03-2021 at 12:08 PM.
    Chris & Karen
    Fort Collins, CO
    2017 F-350 SRW 6.7 Lariat Value CC LB 4x4
    2018 Solitude 310GK

  7. #7
    Site Sponsor
    Join Date
    Sep 2020
    Location
    Central Ca
    Posts
    43
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Camper0414 View Post
    We are towing our Grand Design 5th wheel with a 2020 Chevy Silverado 2500 Heavy Duty Diesel and we received a DEF Fluid warning for 1000 miles. When we check the level it is at 3/4 full. The mileage does not seem correct because over the winter we would fill up with DEF Fluid and it would say 600 - now that we are towing we fill up with DEF fluid it says 360. We are thinking it is because we use more DEF fluid when towing so it throws the formula off and gives a warning. BUT if the truck is going to regulate speed because of thinks it is low we are out of luck. How do we move forward, the truck thinks it is low. The fluid is in there. The system is going to take over. Itís like the brain doesnít the bladder if full.
    The 600/360 number yours shows doesn't seem to be too far off what may be real world numbers of not towing/towing (see below), also YMMV based on how hard it is pulling during trip. Have a friend who has '05 gm and pulling through mountains I look back and see the black smoke coming from his exhaust on numerous occasions (not from ours due to def fluid requirement on newer vehicles), harder pull will use more def.

    Have some numbers as we just got back from 1200mi trip with our setup, from Central Cal through Tehachapi (CA) and I40 (CA/AZ) to Grand Canyon (lots of varying grades throughout the trip) and averaged 10mpg running 60-65mph. Dumped 2.5gal before leaving each way, so used 5gal total of DEF fluid on our trip. Swear both times I saw the same 1000mi message, checked and def level was at the 3/4 full mark also, both messages occurred on a downgrade (not sure if coasting down compared to climbing through elevation throws computer system for a loop or just coincidence). For some reason mine doesn't show remaining mileage for def tank on that screen, just shows the green bar display. 1200mi / 5 gal ~ 240mi/gal def. None towing estimate (taking ownership of truck last Sep) 5900 mi / 7.5 gal ~790mi/gal def. Seems to be in line with few posts of the gm thread - https://www.gm-trucks.com/forums/top...dels/#comments. Seeing my numbers now, I will fill up before trip and carry additional along the way. Also use this link before dumping def fluid in tank for mfr. date/shelf life - https://thecampingadvisor.com/blue-def-date-code/
    2020 GMC 3500 Denali SRW SB Duramax 4x4
    2021 Reflection 31MB Goosebox 16k

  8. #8
    Site Sponsor
    Join Date
    Aug 2013
    Posts
    1,794
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Our 2015 Chevy would warn us at about 800 miles left, then around 500. When the low def light light came on I would add 2.5 gals (20% left in the tank). Never had it shut me down. I did have to get the sensor replaced in the DEF tank (under warranty) though.

    Now my 2019 Ram drinks def. I don't get much more than 1000 miles out of 2.5 gal of def when towing (2000 not towing). Fuel mileage is usually 8 mpg. But this truck is a beast. It has the H/O engine with 4:10 rear gears. No comparison in power to the Duramax with 3:73 rear end and about the same mpg, but double the def consumption. I guess you have to pay for power.

    Red
    Location - Wherever the road takes us...Full-timers
    2015 Momentum 380
    2019 Ram Dually

  9. #9
    Site Sponsor Redapple63's Avatar
    Join Date
    Mar 2020
    Location
    SoCal
    Posts
    416
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    My GMC is woefully inadequate as it relates to DEF remaining. I have found the reporting to be unreliable. I have only gotten the DEF message twice, first time a month after purchase. Clearly the dealer did not add any. Put 6 gals in a 7 gallon tank.

    2nd time was this past December on my way home from a San Diego camping trip. It is only 130 miles from my house. About halfway home I got the DEF warning with 1000 miles message. By the time I got home it was down to 100 miles. All within the span of about 65 miles actually driven.

    To me that message equates to put DEF in as soon as possible.

    Thanks,
    Bill


    Sent from my iPhone using Tapatalk
    2019 GMC 3500 SRW Sierra Denali Duramax
    2020 Reflection 315RLTS

  10. #10
    Site Team WhittleBurner's Avatar
    Join Date
    Nov 2013
    Location
    Meandering through the Carolinas and TN
    Posts
    5,465
    Blog Entries
    19
    Mentioned
    42 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Redapple63 View Post
    My GMC is woefully inadequate as it relates to DEF remaining. I have found the reporting to be unreliable. I have only gotten the DEF message twice, first time a month after purchase. Clearly the dealer did not add any. Put 6 gals in a 7 gallon tank.

    2nd time was this past December on my way home from a San Diego camping trip. It is only 130 miles from my house. About halfway home I got the DEF warning with 1000 miles message. By the time I got home it was down to 100 miles. All within the span of about 65 miles actually driven.

    To me that message equates to put DEF in as soon as possible.

    Thanks,
    Bill


    Sent from my iPhone using Tapatalk

    Our GMC is the same way. Seems like if you are towing or hit a hill, anything that makes you use more power The mileage the to go reduces quite rapidly. When that warning comes on we start looking for a place to get more DEF as soon as possible.
    Marcy & Gary
    2014 Grand Design - Reflection 303RLS
    2015 GMC Denali 3500 Duramax Longbed SRW
    2003 F350 - retired
    Michigan
    We're in trouble now, the dog are bloggin'!
    https://3dogsandatrailer.wordpress.com/


Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

DISCLAIMER:This website is not affiliated with or endorsed by Grand Design RV, LLC or any of its affiliates. This is an independent site.