Originally Posted by Davie200
Yes it's a Cummins 6.7 340 it's at a Freightliner service center where they are also addressing steering problem. I drove it back to storage where light came on I checked the engine diagnostics there were two codes. SPN7854FMI4OC2, SPN7854FMI6OC1. I also figured that they idled the engine moving it around which I would of done. Highway regent in it to blow the soot out. Unfortunately I couldn't as the steering problem was still there so I took it back. Been there for over a week. They claim they were going to do a regen parked there after they changed the sensor. Don't know if that was done as they keep working on steering as test driving it. They are in touch with Freightliner trying to resolve issues. Right now there in process of shimming idler arm or something to that effect than a test drive. I will ask next time I talk to them if regen was done. I had a Cummins in my pickup that would soot up from idling to long and I would take it out and burn off the soot. But that was before DEF process that has become the norm. Thanks for the info. Maybe you can shed some light on this. I'll pass it on.
I have not had a chance to look up the fault codes yet, but if freightliner is involved they are a cummins dealer and should be able to get it fixed right.
I see these kinds of problems everyday it is what I do 5 days a week and I am a cat tech ( certified aftertreatment tech) on both cummins and Detroit engines, and trucks get towed in about 3-4 every week mostly from aftertreatment issue's and is very rare for it to be the owner or drivers fault unless they run out of def fluid or put something else in it besides def fluid or ignored a parked regen request, so being that it is a freightliner chassis 80% are from faulty wiring straight out of the factory like improper routing of wires to wires zip tied to tight and rub on the frame.
But in your case it could be a few things either a wiring issue,or even a plugged air filter will cause excessive soot, as will a stuck open egr valve, but since yours is brand new and they have changed the soot sensor 3 times my bet is a wiring issue.
spn means suspect parameter number
fmi means falure mode indicator
spn is basically the part that failed, and fmi is the fault mode I.E open circuit,low voltage, or not plausible my favorite and that means no matter what scenario you run that engine through you cannot achieve the reading its seeing.
good luck let me know how it goes.