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2015 Chevrolet Silverado 3500 HC DRW 4WD
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Discussion Starter · #1 · (Edited)
I've owned my 2015 for about 10 months and put almost 10k miles on it and some of that has been towing a 18k pound boat. I've never once had the DEF light come on and when I check the level through the DIC it just tells me level OK. I would of thought I would have had to add some by now, is it possible the previous owner could have deleted it?
 

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I don't mean to state the obvious here but did you physically and visually inspect the truck to see if the diesel exhaust fluid equipment was still on the vehicle?

I'm general by 10k towing that heavy you would for sure need to refill it.

If all the DEF equipment is intact on the truck I would say a scan of the ECM to see if a tune has been placed on the vehicle would be the next plan of action.

Do you have any sort of check engine lights or warnings even if it isn't specific to DEF?

2016 LML
 

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Do you know any of the history on the truck? Does it have the stock exhaust on it or does it have an aftermarket exhaust with no dpf and other exhaust components?
My guess is if you haven't put any def in it in 10k miles that it has been deleted and tuned... because that is far from normal for a stock truck.
 
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Discussion Starter · #5 ·
I don't mean to state the obvious here but did you physically and visually inspect the truck to see if the diesel exhaust fluid equipment was still on the vehicle?

I'm general by 10k towing that heavy you would for sure need to refill it.

If all the DEF equipment is intact on the truck I would say a scan of the ECM to see if a tune has been placed on the vehicle would be the next plan of action.

Do you have any sort of check engine lights or warnings even if it isn't specific to DEF?

2016 LML
I've done my share of exhaust deletes on my previous Duramax's but from what I can tell everything is stock. The tank is still there and the tip is the same. There are no knobs or switches that indicate any tune, no rumble through the exhaust either. I haven't looked at the exhaust to see if the muffler or DPF was removed, just because I told myself when I bought this truck I wasn't touching anything on it.

The only history was the carfax and from what I can remember it came from NY and was a municipal vehicle. That's why it doesn't add up.
 

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Something is amiss if it’s not using DEF. Is the tip black inside?
 

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Discussion Starter · #8 ·
doesn’t sound like your to familiar with lml’s.
Hence, the thread. And like I said, I did my fill of exhaust mods on my 06' and 08'. I told myself with this one to not touch anything and just use it for towing. So I haven't really had the need to familiar myself.
 

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Discussion Starter · #9 ·
Something is amiss if it’s not using DEF. Is the tip black inside?
Tip is clean, was told to look for that about a month ago.
 

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Just look under the cab. If it's a straight pipe, there's your answer and it won't be using any def. If you see a 3 foot long muffler-looking thing with a bunch of wires and lines running into it, you know the OEM parts are still there and you should be going through some def.

The black in the pipe thing isn't a 100% test. I've seen a straight piped LML with a clean pipe and I've seen a truck with all the OEM systems in tact that had plenty of black soot in the pipe.
 

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Discussion Starter · #11 ·
Just look under the cab. If it's a straight pipe, there's your answer and it won't be using any def. If you see a 3 foot long muffler-looking thing with a bunch of wires and lines running into it, you know the OEM parts are still there and you should be going through some def.

The black in the pipe thing isn't a 100% test. I've seen a straight piped LML with a clean pipe and I've seen a truck with all the OEM systems in tact that had plenty of black soot in the pipe.
My buddy swears everything is still there, we were under it a few months ago removing the hitch, I don't remember paying attention. I'm going to go out and take another look plus look over the paper work from sale. I'm just curious if someone would go through the trouble of deleting it but not doing any other modifications to it.

Not sure I mentioned it before but the truck throws no codes.
 

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There are some states that conduct "visual" emission inspection, maybe that's why certain things would remain physically intact?

Do you have any type of exhaust note when you drive? Can you heat your turbo spool through your exhaust?
 
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I've owned my 2015 for about 10 months and put almost 10k miles on it and some of that has been towing a 18k pound boat. I've never once had the DEF light come on and when I check the level through the DIC it just tells me level OK. I would of thought I would have had to add some by now, is it possible the previous owner could have deleted it?
My Chevy is pre-DEF but my Ford has a gage like an old fuel gage, so you know how much is left. It also tells you how many miles you have left. New Chevys don't have such a thing? I'd be surprised.
You better add some anyway so you won't get stuck in limp mode
 

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I've owned my 2015 for about 10 months and put almost 10k miles on it and some of that has been towing a 18k pound boat. I've never once had the DEF light come on and when I check the level through the DIC it just tells me level OK. I would of thought I would have had to add some by now, is it possible the previous owner could have deleted it?
DEF is used about 3%, so assuming you are getting 6 mpg towing that heavy load for 10,000 miles that is 1600 gallons of fuel and 50 gallons of DEF, the tank is not that big. Someone has messed with your truck and never told you, bad bad news.
 

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You don't know, until you know
 

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How COULD you notice it would be the more appropriate question.
The SCR system is large and very complicated and has numerous sensors and hoses attached to it. It also runs extremely hot so it is normally covered in heat shields. I went to many seminars about this technology when it was being discussed about making it law and there is a lot of software in the ECU to prevent tampering that is not easy to bypass and often screwed up causing longer term issues. Also the EPA and CARB are really cracking down on deletes and handing out very large fines for bypassing these systems. Unfortunately also any powertrain warranty that may have been in place will also be null now as well. If removed it will also add a lot of NOX to the air which produces the brown pollution we see.

SCR does nothing to reduce the performance of the vehicle as it is purely as passive after treatment, the only downside is the cost of the DEF which adds about 3-4% to your overall fuel cost. There are stories of reliability issues around which while I am sure true are made much worse by aftermarket tinkering and also lack of owner maintenance.
 

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Hook up a scanner and look at nox1 and nox2 values. Nox2 values should be lower. If not, I would guess DEF was programmed out if no DEF codes are found. It's not such a terrible thing. DEF are my only problems that reoccur from time to time.
 

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Hook up a scanner and look at nox1 and nox2 values. Nox2 values should be lower. If not, I would guess DEF was programmed out if no DEF codes are found. It's not such a terrible thing. DEF are my only problems that reoccur from time to time.
I dont think it will be that easy, as if the NOX sensors where operating and the system was gone it would show a code, you have to trick you way around not only the system but the diagnostics which is in a completely separate part of the code to the control system.
 
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