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KWJohn · 10-03-2025, **(Subject: Frequent regens )**

Cummins isx 15/2350. 875k on the engine, and it’s running great. Started having passive regens about twice a day. No check engine lights. DOC PDF cleaned and good. Most sensors are changed. Both dossiers are new. Checked for exhaust leaks, none. SCR is original. Running out of things to look for, any suggestions would be greatly appreciated.

tree98 · 10-03-2025, **(Subject: Frequent regens )**

Is the DPF original? Could be time for a new one, they can only be cleaned so many times.

Will it pass a fuel rail leakdown test with insite?

mikkhh · 10-03-2025, **(Subject: Frequent regens )**

The cans were DRY cleaned in a kiln? Pressure washing or any other wet cleaning damages them and has to be avoided.

Rawze · 10-04-2025, **(Subject: Frequent regens )**

(10-03-2025 )KWJohn Wrote: Cummins isx 15/2350. 875k on the engine, and it’s running great. Started having passive regens about twice a day. No check engine lights. DOC PDF cleaned and good. Most sensors are changed. Both dossiers are new. Checked for exhaust leaks, none. SCR is original. Running out of things to look for, any suggestions would be greatly appreciated.

The passive regens on most ISX's happen about every 5 hours of driving or so. This is normal. Shifting gears a lot or letting it roll down hills in neutral cancels it, and it has to start over.

Are you saying its a lot more frequent that that?.

Post a screen shot or 2 of the regen history screen for some more info.

Also.. when is the last time you did an EGR tune-up on the engine side of things?.
tune-up info: https://rawze.com/forums/showthread.php?...pid=9#pid9

KWJohn · 10-04-2025, **(Subject: Frequent regens )**

Thanks for the help. Passed the bleed down test. Egr tune 2 months ago. It did this same thing about a year ago, finally got a check engine tight. Outlet nox sensor, replaced it and the issue went away. It is currently trying to regen about every 2-3 hours. I can do a forced regen, and it will try again in about 2-3 hours. DPF and DOC were cleaned by DPF alternatives inspected as good.

KWJohn · 10-04-2025, **(Subject: Frequent regens )**

Another piece of information I forgot to share is it will go into high idle mode, sometimes up to an hour before it starts the actual regen.i run Regional on a lot of highways with traffic lights about every half hour or so, and noticed that the exhaust light does not come on.