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+--- Thread: Cm871 Jake solenoids inop (/showthread.php?tid=10809)
Cm871 Jake solenoids inop - dhirocz - 11-05-2026
Engine brake solenoids suddenly quit on me.
The engine still builds boost to Jake… but neither solenoid comes on.
The engine was properly demandated and both the solenoids and the harness were replaced with new Cummins parts close to 300k miles ago when I inframed it.
Since both solenoids quit working at the same time, but I’m still getting boost, I am going to assume that I have an electrical issue, most likely under the valve cover. Is there any hidden relays or fuses that I need to be aware of I should also be checking for while I have things apart?
RE: Cm871 Jake solenoids inop - Rawze - Yesterday
does it show they are on in insite when they are supposed to be active?.
RE: Cm871 Jake solenoids inop - dhirocz - Yesterday
I’ll try to get them to come on today when I go to check over things.
What would cause the ecm to not command them on, but still build boost to Jake?
RE: Cm871 Jake solenoids inop - dhirocz - Today
Looks like they are supposed to be active…pulling the valve cover today to take a look.
RE: Cm871 Jake solenoids inop - Rawze - Today
(Today )dhirocz Wrote: Looks like they are supposed to be active…pulling the valve cover today to take a look.
could be an oil pressure issue on the top end?.
If the crank case filter is clogging up (excessive crank case pressures), it will make the top end starve of oil.