2020 Silverado 2500 DEF usage

redwngr · July 10, 2020

I wouldn't put a lot of faith in the gauge, based on the reports on multiple forums.

Fill it, run it for 3000 - 4000 miles and refill and do a hand calc.

Remember, that the initial warnings are range/miles to empty.

Once it thinks it's empty, there is still 500 miles til the 65 mph speed limit. Should be more than enough miles to get it to the next fuel stop and a def refill location without having any limit on speed.

gSwift · July 11, 2020

19 hours ago, redwngr said:

I wouldn't put a lot of faith in the gauge, based on the reports on multiple forums.

Fill it, run it for 3000 - 4000 miles and refill and do a hand calc.

Remember, that the initial warnings are range/miles to empty.

Once it thinks it's empty, there is still 500 miles til the 65 mph speed limit. Should be more than enough miles to get it to the next fuel stop and a def refill location without having any limit on speed.

Thanks for the info on this.

Just as an update, I put almost 1300 daily driven miles on the truck, haven't towed anything yet, and just tried to add some DEF. Ended up getting about 1/2 to 3/4 of a gallon in it.

cNate · July 12, 2020

Happy to hear you’re getting that kind of range not towing. I just did a 5k round trip towing and hand calculated each full up. Consistently saw between 300-400 per gallon depending on how fast and how much climbing.

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redwngr · July 13, 2020

On 7/12/2020 at 1:29 AM, cNate said:

Happy to hear you’re getting that kind of range not towing. I just did a 5k round trip towing and hand calculated each full up. Consistently saw between 300-400 per gallon depending on how fast and how much climbing.

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Time to update your sig and avatar with the new ride info

cNate · July 14, 2020

Time to update your sig and avatar with the new ride info

Done! Thanks!

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redwngr · July 14, 2020

10 hours ago, cNate said:

Done! Thanks!

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Avatar info update visible (nice truck !)

I'm guessing sigs don't show on tapatalk, but they do in web browser and your sig still has the 2014 info -

2014 GMC Sierra SLT 4x4 CCSB 5.3L 4.10 Yukon gears, Superchips Tune

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AMP Research Power Steps, G4 Elite Fold-A-Cover, Rockford Fosgate 10" 500

GM DQS Tow Mirror Upgrade, Prodigy Trailer Break, Tow Spring

Build Thread

gjohnston7 · July 14, 2020

On 7/10/2020 at 6:22 PM, gSwift said:

Thanks for the info on this.

Just as an update, I put almost 1300 daily driven miles on the truck, haven't towed anything yet, and just tried to add some DEF. Ended up getting about 1/2 to 3/4 of a gallon in it.

Would you continue to track the mileage? I am wondering if there is something different between the trucks made last fall and this spring. I only get about 500 miles per gallon of DEF even when I don't tow anything.

cNate · July 14, 2020

Would you continue to track the mileage? I am wondering if there is something different between the trucks made last fall and this spring. I only get about 500 miles per gallon of DEF even when I don't tow anything.

I just did the module reprogramming recall and topped off my DEF. I’m going to top it off after 1k miles and see what the mileage change is.

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gSwift · July 14, 2020

7 hours ago, gjohnston7 said:

Would you continue to track the mileage? I am wondering if there is something different between the trucks made last fall and this spring. I only get about 500 miles per gallon of DEF even when I don't tow anything.

Yeah i'll keep an eye on it.

cNate · August 2, 2020

So I’ve tracked about 1,600 miles since I topped off the DEF and did the module reprogram. Most of that was towing around California and out to Lake Havasu and back. Hit some grades and average slightly better on my MPG than my last hand calc on def (12 MPG versus my 11 MPG). Got 450 miles per gallon. Better than the 300-400 each time I hand calculated after 1k miles. The sensor also reads accurately all the time now. Will be i retesting to see if I can get close to the 1k per gal mark not towing. Been working remote due to covid and basically only leave if I have the travel trailer in tow these days.

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cr2256 · August 2, 2020

I just picked up my new 2500 on Friday (7/31/20). I have 148 miles and the gauge has gone from full to 1/4 full. I'm wondering if its the gauge or actually using that much DEF?

Hesitated quite a bit on a diesel due to all emission regulation equipment. Pretty frustrating for 2 days in...

gjohnston7 · August 2, 2020

Hi cr2256, I would take to the dealership and see if it has the software upgrades they have released. That should help fix the gauge issue you are seeing. While my DEF usage isn't great, it is definitely not that bad so I think it probably doesn't have the latest software. Once you have that fixed, if you would track your DEF usage for me, I would really appreciate it. I am trying to figure out if my pickup is one off or if across the installed base, everyone is not getting good mileage per gallon of DEF.

cr2256 · August 2, 2020

Thanks, I'll be taking it in early next week. I'll let everyone know if that's what they perform.

Also note that it's a 7/2020 build. Came off the train this last Wednesday in Georgia. Don't know if there is any relationship between build date and excessive usage.

Our family loves the truck besides this.

redwngr · August 2, 2020

10 minutes ago, cr2256 said:

I just picked up my new 2500 on Friday (7/31/20). I have 148 miles and the gauge has gone from full to 1/4 full. I'm wondering if its the gauge or actually using that much DEF?

Hesitated quite a bit on a diesel due to all emission regulation equipment. Pretty frustrating for 2 days in...

Fill the def tank and do your own test.

I probably wasn't full when delivered.

Gauge isn't a typical variable gauge -- it's trying to provide some estimate of how remaining range til empty.

If not full when put into service the calcs will give strange results.

DEF tank not full has caused huge amounts of grief ever since it came in use on duramax for the 2011 model year.

From https://gm-techlink.com/?p=13143

Segmented DEF Level Gauge

The current 2020 Silverado 1500 and Sierra 1500 models have a DEF level gauge on the instrument cluster that provides drivers with a representation of how much DEF is in the DEF tank up. (Fig. 2) The DEF level gauge does not operate like a typical float-style gauge that is used in a fuel tank. The Engine Control Module (ECM) monitors the DEF level and consumption rate in order to calculate an estimated range. DEF levels are detected by the DEF level sensor.

Fig. 2

There may be some fluctuation in the amount of DEF represented on the DEF level gauge. After filling the DEF tank, it may take a few key cycles to register the correct amount in the DEF tank. 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. As a result, a driver could have an initial impression that the vehicle consumes an excessive amount of DEF.

cr2256 · August 2, 2020

@redwngr, thanks and that is possible. The gauge showed full but they didn't confirm that it was filled up during dealer prep. It's possible that it wasn't full to begin with. I need to have something else looked at so ill let them fill it and go from there.

Thanks