Friends 2019 and Regens

cjb2283

Member
Feb 1, 2016
57
0
6
Utah/wherever the AF sends me
So my friend just picked up a 2019 3500 Denali. He got the CTS2 monitor right away. It appears that the truck will get to about 50-55% soot, then jumps up to 100% and starts a regen and is only in regen for about 20-25 minutes. It has done this twice now. I know driving habits and type of driving greatly effects all of this but why would it jump from such a low percentage? He doesn't even have 500 miles on it yet. So about 200 miles between two regens, both doing this jump. Any ideas???
 

trashygasman

Slowly but Surely
Dec 18, 2008
637
1
18
46
Washington, OK
It will do a passive regen at so many miles whether it needs it or not. Mine was doing it at around every 300 miles for a while and is now up to around every 400. I have 7500 miles on mine so far. Don’t remember how often it was doing it when I first got it.
 

2004LB7

Well-known member
Dec 15, 2010
3,370
222
63
Norcal
It will do a passive regen at so many miles whether it needs it or not. Mine was doing it at around every 300 miles for a while and is now up to around every 400. I have 7500 miles on mine so far. Don’t remember how often it was doing it when I first got it.
I don't think you understand what passive regens are. The computer doesn't command them or have any schedule for them. Passive means it happens without having to add any additional fuel for command anything else to get it to happen. It normally occors when under a sufficient load for a long enough time to keep the EGT high enough to burn off the soot on it own.

Active regeneration happens on a schedule/fixed number of miles and or by soot load. This is done usually by the addition of extra fuel dumped into the exhaust upstream of the DPF. This will "burn" and raise the temp to the point where it can burn off the soot.

Earlier methods usually employed reducing injection timing and or using large post injections. This was the LMMs method. This was very noticeable while driving

Later models added a "9th" injector into the exhaust to add the needed fuel. This meant that no timing or fueling changes where needed to the engine itself so it was barely noticeable while driving. Of course the DPF and regen fuel still needed the extra air to burn properly so an elevated idle would be used to obtain this
 

2004LB7

Well-known member
Dec 15, 2010
3,370
222
63
Norcal
:thumb:

Yeah, I think it is miles, gallons and soot level. What ever comes first triggers the regen
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
18,104
387
83
Phoenix Az
700 miles is the scheduled amount for mileage. I dont think there is a gallons amount but nothing to back that.
 

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