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2021 LTZ 3500 Midnight Edition
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Saw a couple of posts on this but still looking for advice. -10 here in Minnesota. I normally plug in my truck in but it sat out at work all day so I didn’t plug it in. Started the truck and let it warm up 5 minutes and got the Service Emissions message on the dash as well as the 65mph limit in xxx miles message which you cannot exit out of. For those that got this message, do you think I should just drive it and see if it goes out? My gut tells me it is related to DEF tank freezing.
Side note, I have a banks pedal monster installed, and thought this may cause it as well. I remove it to see if it goes away as well.
 

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Do you have an iDash or any kind of code reader? That would help a lot.
 

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Yeah just picked one up. I’ll see what codes are displayed.
 

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Frozen def doesn't cause either message.
 

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Sounds like DEF tank is history. Dealer told me they are failing in a large percentage of these trucks and back order is 3 months. Wow...
 

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I got the same message the other day and truck went into “limp mode” DIC says service emission system. Checked for codes and got P0106. MAP/ barometric pressure. I spoke to service this AM and was told it has to do with the placement of the sensor. Apparently the sensor can freeze if you’re not using the front cover?. I’m not sure if this is the actual cause of the problem, but I’m going to install the cover and see.
2020 Denali 3500 HD with 6000km’s
 

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I got the same message the other day and truck went into “limp mode” DIC says service emission system. Checked for codes and got P0106. MAP/ barometric pressure. I spoke to service this AM and was told it has to do with the placement of the sensor. Apparently the sensor can freeze if you’re not using the front cover?. I’m not sure if this is the actual cause of the problem, but I’m going to install the cover and see.
2020 Denali 3500 HD with 6000km’s
HUH? the MAP sensor is on the cold side pipe right before going into the heads.. POST turbo.. so its still hot air..

now the MAP can get sooted up since they have placed it post EGR as they use it to monitor EGR performance.. and actually its not a MAP sensor.. its a TMAP (temp AND pressure)

its a simple 10mm bolt sitting right on top to pull it out and see if it needs a cleaning...

however.. with the rash of unbeleivable cold weather it just may be that the DEF system is freezing up..

i read a paper on how that system works.. and man talk about complicated..

when the engine stops, after a delay, the DEF fluid is reverse pumped out of the lines to ensure they don't freeze there..

when the engine is started in cold weather there is a programmed delay before DEF monitoring occurs to allow the systems heaters in the DEF tank and and circulation of coolant to the DEF injector have warmed things sufficiently..

the DEF,EGR,MAF,MAP,O2,NOX,DOC,SCR all have to work together to meet the programmed expectations of the ECM ... if any of these values wander out of the limits.. it assumes you are monkeying with the DEF or EGR systems and penalizes you with reduced performance.. the DEF NOX issue would not cause any kind of engine damage.. this programming is strictly to punish emissions cheaters.. but unfortunately for ever 1 of those the system is 'catching' the over zealous programming is malfunctioning for THOUSANDS of others...

now as far as freezing up sensors without a cover.. the only one I can even remotely by would be the MAF since its just past the air filter and I call BS on that too..

I WILL say that these L5P trucks seem a LOT more dependent on using that block heater in accordance with the owners manual temperatures.. because again.. if you read the logic behind how the DEF SCR works.. alot hinges on the NOX reading being in line within a set amount of time after engine start.. otherwise.. code city...
 

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I’ve had LLY, LML and now L5P and this will be the first time being told “ I have to use“ the winter cover.
The service guy at the local dealer I spoke to this AM said they had 7 trucks in on Saturday all with the same problem, many of them towing snowmobile trailers. Once they were warmed up/ thawed out the problem went away?! Don’t know for how long or......
Funny thing is, it says on the instructions for the front cover “remove if towing”
I’m going to limp mine to my purchasing dealer about an hour away this afternoon, I’ll update after.
cheers!
 

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All it takes is one sensor to read out of an expected value and you'll get a light. Boy this polar vortex is really messin with these trucks.
I count my blessings on my 2010 that's for sure. Most I have seen is a glowplug failure, but we are winter mix fuel up here in NY.
 

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Boy we never have long enough snow as it is. If a down truck messed with my snowmobiling i'd be wound up!
 

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I’ve had LLY, LML and now L5P and this will be the first time being told “ I have to use“ the winter cover.
The service guy at the local dealer I spoke to this AM said they had 7 trucks in on Saturday all with the same problem, many of them towing snowmobile trailers. Once they were warmed up/ thawed out the problem went away?! Don’t know for how long or......
Funny thing is, it says on the instructions for the front cover “remove if towing”
I’m going to limp mine to my purchasing dealer about an hour away this afternoon, I’ll update after.
cheers!
there are a lot of dumb design issues here that I don't thing GM took into account when they designed the system...

the frame mounted filter is exposed to cold air and when running down the highway... high speed cold air..

the in tank lift pump has a filter sock.. so when the fuel begins to cloud and percipitate ice crystals and parrafin solids.. its plugs up the sock... and starves the lift pump

there is no fuel heater like on many diesels and ALL military vehicles that I can recal

I am sure that the duramax supplements call for block heater at temps most people scoff at and say its not needed don't understand the the reason its there is that when GM started doing cold weather testing and found all these issues .. it was going to be too expensive to re-design and those things 'helped' but likely didnt eliminate the problem

read this doc and tell me that the DEF system isn't overly complicated and poorly designed..
further.. most of these emissions codes are being thrown likely because the ECM isn't seeing NOX values get into limits fast enough because of the poor cold weather performance and programmed logic of the DEF system.. all these messages about DEF and emissions .. none of it would hurt the engine.. the reduced power and MPH setepdowns are there to punish people the computer thinks is trying to defeat emissions.. but is not programmed correctly to take these extreme operating conditions into account and malfunctioning for far too many people that are not messing with their trucks..
 

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i gave up snowmobiling a couple years ago, but I was pissed that I had to limp home halfway thru a 4 hour trip to move my daughter. -13 C here right now, guess I’ll go out with a bucket of warm water and clean the road salt and shit off my grill and install the winter cover!
Just came in from snowblowing a foot of snow. Thank god the Kubota doesn’t have emission shit.
cheers.
 

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i gave up snowmobiling a couple years ago, but I was pissed that I had to limp home halfway thru a 4 hour trip to move my daughter. -13 C here right now, guess I’ll go out with a bucket of warm water and clean the road salt and shit off my grill and install the winter cover!
Just came in from snowblowing a foot of snow. Thank god the Kubota doesn’t have emission shit.
cheers.
one of these days GM is going to face a negligent homicide lawsuit if someone gets stranded in arctic conditions just because of faulty programming...
 

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one of these days GM is going to face a negligent homicide lawsuit if someone gets stranded in arctic conditions just because of faulty programming...
For sure!
 

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my 16 kubota 4701 has emissions. Had to do an exhaust burnoff already and boy she cranks the RPMS when that happens.
Thanks for sharing the doc duece, i enjoy the light reading being of engineering background (mechanical)
 

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Wow great posts and a great education on emissions guys. Thanks.
This is my 3rd generation of diesel (Ford, ram, and now Chevy) and all of them gave me some sort of fits when weather drops -10 or lower.
It would be good if I could reset the emissions “countdown” knowing it’s just cold weather. Anyone know how to do this? I’ve tried disconnecting battery and also tried odbc code erase from my reader but it isn’t throwing any codes.
 

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there are a lot of dumb design issues here that I don't thing GM took into account when they designed the system...

the frame mounted filter is exposed to cold air and when running down the highway... high speed cold air..

the in tank lift pump has a filter sock.. so when the fuel begins to cloud and percipitate ice crystals and parrafin solids.. its plugs up the sock... and starves the lift pump

there is no fuel heater like on many diesels and ALL military vehicles that I can recal

I am sure that the duramax supplements call for block heater at temps most people scoff at and say its not needed don't understand the the reason its there is that when GM started doing cold weather testing and found all these issues .. it was going to be too expensive to re-design and those things 'helped' but likely didnt eliminate the problem

read this doc and tell me that the DEF system isn't overly complicated and poorly designed..
further.. most of these emissions codes are being thrown likely because the ECM isn't seeing NOX values get into limits fast enough because of the poor cold weather performance and programmed logic of the DEF system.. all these messages about DEF and emissions .. none of it would hurt the engine.. the reduced power and MPH setepdowns are there to punish people the computer thinks is trying to defeat emissions.. but is not programmed correctly to take these extreme operating conditions into account and malfunctioning for far too many people that are not messing with their trucks..
You got to love engineers...
 

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Well...i am unsure of a completely simple way to comply with the mandates of the feds unfortunately. BUT I also can appreciate the sentiment (being an engineer), and scratch my head sometimes when i see some of the stuff out in industry. Guess same as the age old saying, whether a doctor passes his tests by an inch or a mile, he's still a doctor
 

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Was around 10 degrees F when I started this am. Down to -1 earlier. 2021 Sierra 2500 Dmax. Was plugged in all night. Made some unexpected buzzing/whistling sounds. Seemed to come from below the due/def fill area. I took a video with audio but unable to attach it.

My first diesel, 409 miles on the clock.

Noise went away after 15 minutes or so. Ran fine but didn’t exceed 40 mph based on conditions.

Is this one of the “normal” noises I should expect in low temp conditions?

Edit Here is a link: iCloud



Sent from my iPhone using Tapatalk
 
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