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What are other owners of a 2020 Silverado 2500 Duramax getting as far as DEF usage?

 

I have a 2020 Chevy Silverado 2500 Duramax that is only getting about 300 miles to a gallon of DEF.  My last pickup was a 2016 Silverado 3500 and I was getting over 1,000 miles to a gallon of DEF.  Pulling the exact same trailer, with the same loading, going the same route.  Without a trailer, just driving around town I am getting a whopping 400 gallons.

 

I have taken it to the dealer a few times and they say without an error code, there is nothing wrong.  They have updated the software a couple of times and given me a bulletin from Chevy that said higher usage might be from changing environmental standards.  Looked up the standards and they didn't change that much.  I assume that is why they went from 5 gallon tank to 7. 

 

Is everyone experiencing this same level of usage with the 2020 or is my "unique"?  Or did I have an unusual experience with the 2016?  I have only driven Chevy Silverado diesel pickups and have never had any issues but this experience is just about to tip me over the edge and consider something different.

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It would be helpful to know more details: travel trailer, fifth wheel, how long, how much does it weigh, where  and how far exactly are you towing.  How fast do you tow?  Mountainous terrain or mostly flat makes a difference.

 

I haven't towed with mine yet but I'm going out next week for the first time with a travel trailer.  I'm not using much DEF in normal driving but I'm sure the truck will use more with a load behind the truck.  We'll see!

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I am pulling a 24' gooseneck.  Loading is about 6,000 pounds.  Freeway speeds.  Over 4,000 miles.  Like I mentioned earlier, it is the exact same loading, route and speeds that I drove with my 2016.  With my 2016, I could do the entire 4,000 mile trip and fill-up the DEF tank when I returned.  Now it is giving me the 999 mile notice after driving 300-400 miles.  

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2020 dually, 20+8ft gooseneck enclosed trailer.  Weight range between 8000-15000lbs, 80% highway 65-75 mph, using over twice the def as my 2016 ram 3500, same trailer, same speed, same route.  The consumption is 5-6 tanks of fuel to a full tank of def.  The consumption i could live with if they had made a bigger tank.

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I agree.  I only go about 400 miles and I get the warning that I only have the 999 miles to go.  Great that they finally put the DEF by the fuel cap instead of under the hood but they definitely have missed the boat on usage with this generation.  They should have made the tank 3 times as big.  I think there is something wrong with the design or system.  It is a pain to fill DEF all the time.

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Im pretty sure there is a TSB for high DEF usage.  Remember seeing something either on these forums or the duramaxforums

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The TSB that the dealership gave me was one that they justified the increase of usage on regulatory changes.  When I did a search, it looked the standards changed 10-15%.  I assume that is why they went from a 5 gallon to a 7 gallon DEF tank.  However, That would not explain why I went from over a 1000 miles per gallon of DEF to 300.  Since the system doesn't generate an error code, Chevy says there isn't an issue.  Instead of looking at the data and saying that doesn't make sense they are only interested in error codes.  Or I would prefer that they come out and say, yup - you are only going to get 300 miles per gallon of DEF.  

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On 6/17/2020 at 6:37 AM, gjohnston7 said:

The TSB that the dealership gave me was one that they justified the increase of usage on regulatory changes.  When I did a search, it looked the standards changed 10-15%.  I assume that is why they went from a 5 gallon to a 7 gallon DEF tank.  However, That would not explain why I went from over a 1000 miles per gallon of DEF to 300.  Since the system doesn't generate an error code, Chevy says there isn't an issue.  Instead of looking at the data and saying that doesn't make sense they are only interested in error codes.  Or I would prefer that they come out and say, yup - you are only going to get 300 miles per gallon of DEF.  

My 2019 is getting 850 miles per gallon give or take yours seems pretty steep indeed.  Gm should tell what the milage should be relative to the fuel burn...  Maybe a call to corporate or another dealer

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Thanks Curver900.  Appreciate the data.  All the data I get from other users is extremely helpful. I called corporate and they referred me back to the dealer.  

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Posted (edited)

Hey guys, I picked up my 2020 Silverado 3500 srw duramax last month and took it on a road trip of about 2,000 miles pulling my old Jayco travel trailer (about 6,000 lbs loaded). I was burning through DEF like crazy and wound up on the first day getting an engine code...lucky for me I have a bluetooth OBD scan tool so I pulled over and plugged in. I was getting a P2002 error code "Diesel Particulate Filter Efficiency Below Threshold Bank 1, which refers to an issue in the efficiency of the particulate filter in the exhaust, which is most likely caused by faulty filter or sensor, or exhaust leak." From what I could tell online it wasn't a "major" issue to halt our trip so I continued on and went ahead and setup a service appointment for after our trip was over. I BURNED through DEF on the trip. I filled up twice!!

 

Skip ahead to the dealer and come to find out they had to do a "cheese cloth test" to see how many particulates were getting through and I'm getting a brand new exhaust on my new truck because the DPF sensor is built into the exhaust. It's at the shop today getting replaced so hopefully that resolves my issue and I get to a normal DEF usage with no constant engine code.

 

Just figured this was worth sharing.

Edited by Alan Juden
"cheese grater test" --> "cheese cloth test"

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everything you all are talking about is what i experienced when i picked up my truck in December.  i went to the dealership and delt with GM...eventually they just hung up on me after telling me the truck is operating within specs...hope something comes out so i can stop carrying 2 extra 2.5 gallons DEFs around with me at all times

 

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I got my brand new exhaust on Friday and only drove a couple times since then. However, they gave me some paperwork with a reference # of 20-NA-082. They're basically saying in the paper that newer model trucks have to use more DEF because of the increased emissions requirements.

Quote

 

Subject: Information on Excessive Diesel Exhaust Fluid (DEF) Usage

 

Condition: Some customers may comment that excessive DEF is being used. Some technicians may find no codes set or messages on the DIC.

 

Information: The current 2020 Silverado/Sierra is the first to have a DEF level gauge on the IP. This is the first time a customer can see a representation of how much DEF is in the tank up to the full capacity of the tank. This gauge does not operate like the float style gauge that you have in your fuel tank. Because of this, you may see some fluctuation in the gauge. It may also take a few key cycles to register the correct amount in the tank after a fill event. With the new segmented DEF Level gauge, it is possible that after adding 5 gallons (18.9 L) of DEF that the gauge reads as a full tank after the fill event. However, if the actual level of DEF is just entering the last segment on the gauge, the gauge is likely to drop by one segment shortly after driving after the fill event. This could give an initial impression that the vehicle consumes a lot of DEF.

 

Every year that GM produces vehicles with diesel engines, the requirements to reduce Nitrogen Oxides (NOx) in the vehicle exhaust continue to get more aggressive. Because DEF is required to reduce the NOx in the exhaust, DEF consumption will increase as NOx reduction requirements increase. When customers trade in an older model year diesel Silverado/Sierra for a newer model year, there will likely be an increase in DEF usage. DEF consumption increases as the newer vehicles meet the more stringent emission requirements for that model year.

 

The amount of DEF usage is also a function of how hard the engine is working, or engine load. Because of this, it is more representative to compare DEF usage to the amount of fuel used, also a function of engine load, instead of miles traveled. In addition to engine load, other factors that affect the DEF usage rate are the humidity, temperature, and under certain conditions, the ECM will increase or decrease the amount of DEF based on learning or adaptive algorithms. In the event of a malfunction and SES light, the ECM may double or even eliminate the amount of DEF that is being used. This will continue until the vehicle is repaired and until the learned value in the ECM is reset.

 

 

Hope this helps you guys!

 

Alan

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Hi Alan.  Thanks for the post.  The dealer did give me that but I don't think it is the whole story.  My usage when from a gallon of DEF per 1000 miles to 300 miles.  That is a huge drop that I don't think matches the regulation changes that I have found in my research.    I have friends that have new Fords and Dodges and they are seeing the over 1,000 per DEF like I used to.  If it was all attributed to regulatory requirements, I would think the entire industry would be seeing the same impact on usage.  I would be interested in what kind of DEF usage you are experiencing.   I am trying to figure out if it is just few people that are seeing this kind of usage or if it is much broader across the 2020 Silverado customers.

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I'll keep an eye on my DEF usage and report back after I have some data but I don't have any trips planned for a couple weeks.

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