2025 Cummins Regen Observations

[scdo]

i had the larger screen in my 21 and it showed it as well. my idash shows it in regen as well. as much as my truck has in it tech wise, why id didnt have the bigger screen dash is odd but what ever lol

The "all-digital" screen does not display the regen even when showing the DPF gauge.

 

[HarryN]

Some vehicles have a way to manually trigger a cycle - to run when it is convenient like during a longer drive. Is there any option to do it this way ?

 

[scdo]

Some vehicles have a way to manually trigger a cycle - to run when it is convenient like during a longer drive. Is there any option to do it this way ?

Not really... you can trigger a stationary active regen with Alfa or JScan (if/when they add support to the 2025s) I believe but there's nothing in the vehicle to enable this directly. I'm hoping regens on the 25 are simply something that will fall to the background and be a non issue / no driver intervention required. We shall see.

 

[Brutal_HO]

Some vehicles have a way to manually trigger a cycle - to run when it is convenient like during a longer drive. Is there any option to do it this way ?

Not really... you can trigger a stationary active regen with Alfa or JScan (if/when they support to the 2025s) I believe but there's nothing in the vehicle to enable this directly. I'm hoping regens on the 25 are simply something that will fall to the background and be a non issue / no driver intervention required. We shall see.

The CC trucks have a factory/dealer option for manual regen but when I tried to enable it on my 2020 3500 HO, I could never get it to work. The button would show up, but it wouldn't' do anything. Likely also tied to the platform vehicle code.

 

[mbarber84]

i had the larger screen in my 21 and it showed it as well. my idash shows it in regen as well. as much as my truck has in it tech wise, why id didnt have the bigger screen dash is odd but what ever lol

There are 3 different EViC’s for 23+ trucks.

3.5” partial analog, 7” partial analog, and 12” fully digital. Only the 3.5” and 7” are capable of providing the normal regeneration message (when scrolling to the DPF page). The fully digital 12” does not provide normal regeneration messages, it is only capable of providing the regeneration message in the “intervention” mode (when it says “continue driving”)

I’m betting the same holds true for 2025+

I have no idea why the 12” will not give that message ( wether it was an accidental omission or an intentional removal of that feature)

 

[scdo]

UPDATE

I haven't driven a TON yet (at 1,200 miles). Since that first regen, I've done a mix of city and highway with a majority of short trips. There were a couple longer stretches but this is mainly day-to-day driving. After ~ 11 hours, I'm at 10% on the EVIC and reading ~ 45% on my OBD reader. Performing far better than my 23 was.

I have a long RV trip planned in a month and will be using it as a daily driver between now and then.

 

[scdo]

Another Update

I made it another 24 hours. 10% on the DPF gauge. This was mixed city driving… a lot of short trips tbh. It looks like this new system is working much better.

First big RV trip from Phoenix to Zion in Southern Utah in a few weeks!

 

[m.stephen.miller]

I haven't quite nailed down the regen logic (or DPF loading) on my 2025.

The first 24 hours were a mix of city and highway, with many short trips. Made it to about 30% on the EVIC DPF gauge, and the regen triggered on time at 24 hours. Being back at 0%, the next 600 miles were all towing our ~8500 lb travel trailer at 60 - 65 mph, and the DPF steadily went up from 0% to 30% at the end of the trip. That must not have been enough load for passive regen temps, but I was surprised that the DPF was filling up quickly under those conditions.

The second regen triggered around 13 hours and 40% on the gauge, but while I was running a few trips around town. After a few 10 min trips under regen, the gauge was down at 30% and the regen did not initiate for the next start. The next trip after that was about a 45 min highway ride at 75 mph and the gauge is still at 30%.

So far, oddly - soot loading seemed better with mixed city/highway (24 hour regen) than towing a trailer at highway speeds only (12-13 hours), and the regen seemed to quit after a few tries even though the DPF gauge was only brought down to 30%. It does seem obvious when the regen is happening, as the truck is a bit louder (when in gear only), and the smell is distinctly different from outside of the truck.

I am wondering if passive regen will be more difficult to achieve on these trucks, and if there is some kind of timeout on the attempts for active regeneration if it doesn't complete (but at least brings it below some threshold value).

 

[Units]

the next 600 miles were all towing our ~8500 lb travel trailer at 60 - 65 mph, and the DPF steadily went up from 0% to 30% at the end of the trip.

Very strange, I pull my #7000 TT and not more than about 30 minutes my DPF gauge jumps down to zero and says there. Mines a ‘23 so the regeneration strategy is surely different, that coupled with the changes to the exhaust non towing passive regeneration will no doubt behave differently but not going down to zero and continuing to build while towing is strange. So, you’re saying while towing the DPF gauge continued to climb?

 

[m.stephen.miller]

Very strange, I pull my #7000 TT and not more than about 30 minutes my DPF gauge jumps down to zero and says there. Mines a ‘23 so the regeneration strategy is surely different, that coupled with the changes to the exhaust non towing passive regeneration will no doubt behave differently but not going down to zero and continuing to build while towing is strange. So, you’re saying while towing the DPF gauge continued to climb?

Correct. I don't have an iDash or any other way to monitor EGTs, so I can't comment on that. The original post in this thread indicates similar behavior when unloaded (up to 30% after 700 miles of highway speeds), but I haven't seen much feedback from others while towing with their '25s. Towing was in T/H mode and mostly 8th gear and 1500 rpm, with some time in 7th for spots with more hills. I could have locked out 8th but I don't think that improves temperatures or soot load.

 

[scdo]

I’m at 20% on the dash after 13 hours of short tripping. Leaving tomorrow with the camper so we’ll see what happens!

 

[m.stephen.miller]

Have a safe trip.

I will mention that the new 3500 barely seemed to notice the 8500# trailer, other than some drop in fuel economy. In alt-trailer height, everything was ultra stable even in cross winds, which made for a very enjoyable ride. With the tow-mode DRVM, it was actually easy to forget the trailer was connected.

 

[LBSAND]

My 3 regens have come at 867mi, 568mi, and 386mi. I'm mostly unloaded on a 35 mi straight shot to work and travel 75 to 80mph. The last two regens happened with only 10% on DPF gauge. My CTS3 that I had on my 22' killed my batteries and I had to take it off so I don't know what temps are doing.

 

[AH64ID]

My 3 regens have come at 867mi, 568mi, and 386mi. I'm mostly unloaded on a 35 mi straight shot to work and travel 75 to 80mph. The last two regens happened with only 10% on DPF gauge. My CTS3 that I had on my 22' killed my batteries and I had to take it off so I don't know what temps are doing.

Miles aren’t what the computer uses for regen frequency, hours are.

Interesting on the CTS3. I’ve never noticed an excess draw, so I don’t think it’s normal. Did you contact Edge? Their customer support is pretty good.

 

[mbarber84]

Without having a CTS3 or iDash hooked up, it would be hard to guess what the new 25’s are doing in terms of EGT’s while towing, especially if it was running at 1,500 rpm under load. Historically, I wouldn’t expect the soot load to climb while towing at highway speed, provided you were towing something of reasonable weight or resistance. The travel trailer should be enough in my mind, but hard to say for sure. This behavior seems a little suspicious to me. I wouldn’t expect them to change the regen strategy much, but I could believe they may have tweaked it some in order to reduce the possibility for a frequent regen scenario, especially in cases where they’re cycle is routinely interrupted.

 

[AH64ID]

There is also a strong possibility that the dash has been reprogrammed, especially since most 25 owners seem to be reporting more movement on the DPF gauge.

 

[mbarber84]

There is also a strong possibility that the dash has been reprogrammed, especially since most 25 owners seem to be reporting more movement on the DPF gauge.

I think you might be right. I haven’t had a chance to drive one yet, but I’ve seen a few pictures posted. Looks like the instrument cluster guage now shows movement in 10% increments maybe? That would be a big change compared to 24 and older. We may now be getting better data that would parallel the PID information rather than only showing the last few incremental climbs before a soot based regen kicks on.

 

[m.stephen.miller]

I can confirm the dash displays the DPF in 10% increments. My first regen was at 24 hours, and the second was when the DPF reached around 40%. I don't think the regen strategy changed, other than maybe to avoid frequent attempts without completion.

Can't comment on EGTs, but it certainly didn't feel like the engine was working hard in 8th gear and 1500 rpm. I wouldn't be too surprised if the temps weren't high. I believe scdo has iDash and is on a towing trip, so we'll see what they report back.

 

[Brutal_HO]

With the 7th injector, I wouldn't expect the engine to be working harder (raising EGT) to avoid or assist regen.

 

[m.stephen.miller]

With the 7th injector, I wouldn't expect the engine to be working harder (raising EGT) to avoid or assist regen.

I wasn't expecting it, but there's definitely a low end grumble when in regen. Sounds like light exhaust braking, but only when in gear and most noticable at idle or low speed