X15 constant regeneration

[Therealarw]

Hi everyone,

I’ve come across one of my trucks and I’m completely stumped on it… It’s a 2019 Peterbilt with an X15 engine in it.. lately it’s been going through a regen almost every single day. Constantly just high rpm at idle when the truck is stopped even when the parking brake isn’t set it goes off. There’s no check engine lights for it nothing inactive or active either. I had an extra DPF DOC and the SCR catalyst from another truck (everything was the same for part numbers) and it’s still going through this regen stage… Only things I haven’t done on it are an ECM calibration, or ran the rack on it or checked the injectors. From what I understand these engines don’t have a 7th injector and instead the 6 fuel injectors are what atomize the fuel that goes into the exhaust system. Another thing before I forget is that I did the aftertreatment maintenance reset when I did the filters. I feel like I’ve looked through about everything on the truck but maybe I am missing something? Part of me feels like maybe the ECM might be glitched and it’s seeing something either pressure or temperature related that actually might be false causing it to constantly regen? I’m not too sure but it’s been a pain in the a** and the driver who drives this trucks worried that it’s gonna eventually hurt the motor. Thank you guys for checking this out and hopefully we can figure this out!

Thanks!
Adam

[marek4792]

Did you do a full EGR tune up? - https://rawze.com/forums/showthread.php?...7#pid73167

Have you done injector leak tests on it?. - https://rawze.com/forums/showthread.php?...3#pid75483

Do you have oil consumption more than 1 gallon every 4,000 miles or equivalent hrs?

Did you check the regen history? The InHg shouldn't be more then 3 consistently.

Did you take the down pipe off and snap test to check for large amount of smoke?

Have a friend with a 565 x15 that had similar symptom with daily regens that upon snap testing with the downpipe off literally smoke out the shop, luckily he was at a stealership that knows what to look for instead of blindly following a diag tree.
He got a full set of injectors under warranty luckily...
I personally had a injector not atomize properly (white smoke) that cracked manifolds and eventually the turbo itself until I caught it doing a snap test with the manifold off...
Also recently had an injector get stuck under full load, it didn't misfire either letting off, EGT would go the moon until i freed it up and ran good until being replaced..
You need to figure this out before you service the cans and not fire the parts cannon like the stealerships usually do!!

[Rawze]

(08-10-2026 )Therealarw Wrote:  ...Only things I haven’t done on it are an ECM calibration, or ran the rack on it or checked the injectors. ...
Thanks!
Adam

First of all,.. take the cans to an OEM stealers$it and have them baked, de-ashed, and flow tested. - the truck engine regen process is incapable of cleaning the DPF fully, and only converts soot into ash that it cannot get rid of.

Make sure any cleaning process while they arer removed does NOT use any liquids, as they will wash out the precious metals, and make DPF half as effective... leading to nox, regen, and other issues.

Also, Re-flashing the ecu software, even if it is the same version, will force-reset all the data in the ecm and make it establish a new base-line. This is far more effective than simply doing maintenance resets... especially if you replaced the cans with new ones.


and yeah... the issues are at the engine not the cans under the truck.. fix the engine .. a full egr tune-up/cleaning, injector tests/replacements, overhead valves, etc.etc. - like was mentioned in the post above.