2020 W900L, X15 at 565, 612k miles. for about three weeks the dash wants a parked regen every 150 to 200 miles. used to be never, the truck did it on its own going down the road. no check engine light, just the regen lamp and the soot load number climbing.
did a parked regen at a truck stop in Dickinson, went fine, 40 minutes. by Glendive it was back at 70 percent.
dealer in Fargo wants to start with a DPF clean at 1,100. i'd rather not spend that if the filter is the victim and not the cause. where should i look first?
good instinct, don't start with the filter. when the soot number climbs that fast either the engine is making the soot or the ECM is being lied to about it. my order on an X15 with that pattern:
1. are you adding coolant. a leaking EGR cooler makes soot and eats coolant, pressure test the cooling system if the level moves at all.
2. run the EGR valve test with Insite, a valve sticking open does the same thing.
3. leak test the charge air cooler and the boots. a cheap kit and 20 minutes.
4. the DPF differential pressure sensor and its two hoses. a cracked hose reads wrong and the ECM thinks the filter is loaded when it isn't.
number 4 is what i find most on trucks that sit outside up north. the hoses crack right at the clamps.
coolant level hasn't moved, i mark the jug with a paint pen. i'll look at the pressure hoses tonight, they run down under the cab by the step and they're crusty.
found it. the front pressure hose had a split right at the clamp by the DPF inlet, you could see soot tracked out of it. 14 dollar hose at the Cummins shop in West Fargo and a 20 minute swap. cleared the counts, ran to Jamestown and back loaded, soot load sat around 18 percent the whole way. no regen request since.
the dealer was going to clean a filter that didn't need cleaning.
saving this one. mine did the same thing on a 2018 4900 with the ISX, only it was the sensor itself, the reading drifted high. 380 for the sensor.
worth saying too, if you do a lot of short hops or idle a lot the DPF never gets hot enough to clean itself going down the road, and you get this same pattern with nothing broken. heavy haul at 30 mph behind a pilot car is the worst for it.
close enough to ask here. how often should the DPF really get pulled and cleaned on an X15 running regular highway? my shop in Des Moines says every 400k. what i read in the manual sounded like it goes by hours and fuel burned, not miles.
it goes by ash, not miles. the ECM keeps an ash load estimate and it will tell you when. highway trucks on a low ash oil that meets the spec for your engine usually go 400 to 600k before the ash number says clean it. heavy idlers sooner.
cummins has the maintenance intervals by duty cycle on cummins.com, look yours up by engine serial number before you let anybody sell you a clean.
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