Cummins isx cm871 fault 2637

[JimT]

(11-01-2022 )Mrt800 Wrote:  Same time I replaced the dpf I got the doc cleaned out ,also new dozer ,sensor , temp etc.
I replaced the egr and did the tune up . I noticed that the imap sensor was carbon
Packed completely.

Not sure why the DPF was replaced, but the DOC also wears down over time. Often when the DPF reaches the age of replacement the DOC is usually due as well. The precious metal coating wears down and doesn't react as well, or at all. Doesn't take much non-ignited fuel to coat the DOC and then attract soot build up and clogging. Also, leaking fluids, especially coolant, can wear away at the DOC's reactive coating causing reduced performance and shorter life span. Simply put, it's often the case that the DOC should be replaced along with the DPF.

This isn't to imply that you don't have some other issue or issues, but as the DOC conversion efficiency degrades over time you will get longer and more frequent regens, less efficient soot burn off and more clogging as soot builds up. Probably not even noticeable until it either gets really bad or something else further impacts the system.