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Ask Geoff Your Own Question
Geoff, Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 40
Experience:  Fleet Maintenance Training Instructor at Washington Metropolitan Area Transit Authority
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Have a 2008 isb 240 that keeps setting stop engine light

Customer Question

have a 2008 isb 240 that keeps setting stop engine light for high crankcase pressure
we put it on a dyno at a dealer ad were told particulate filter pluged so we removed the filter for testing same light as well the dyno test showed engine in good shape even with 500k on it
took it to an independant who had worked on the truck alot and he saidit has high crank case pressure although he had said the same thing as cummins just 2 trips to him ago he changed the crankcase filter about 10 k ago said pressure was fine
i see alot of concern about plugged drains etc on this system and a referal to emc calibration i cannot find procefure 019-032 in section 19
also can not find the trouble tree for crankcase gasses blowby excessive i have
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Geoff replied 1 year ago.

Hi, my name is ***** ***** I'd like to help. First, I'd like to get some clarification on your issue. You mentioned that you were getting a code for high crankcase pressure. Do you mean, Crankcase Pressure - Data Valid, but Above Normal Operating Range? I just want to be sure I'm helping with the correct problem. If you could provide the fault code number, that would be even better. I'm a bit uncertain as to why someone would tell you that a clogged DPF would trigger this code. A clogged DPF would set code, Aftertreatment Diesel Particulate Filter

Expert:  Geoff replied 1 year ago.

Aftertreatment Diesel Particulate Filter Differential Pressure Sensor - Data Valid but Above Normal Operating Range. When you have high crankcase pressure, the first step is to inspect the crankcase filter and draft tubes. This is the most common cause for this code.

Expert:  Geoff replied 1 year ago.

If you can confirm exactly which code was active, I can provide with the trouble tree if that's what you would like.

Customer: replied 1 year ago.
On my telemetry i am seeing mid128 crankcase pressure (pid101) is data valid but above normal operational range ( fmi1)
Expert:  Geoff replied 1 year ago.

Ok. Just wanted to make sure your code didn't indicate a failed sensor. You mentioned wanting the trouble tree for this code. Would you still like me to upload it?

Customer: replied 1 year ago.
Expert:  Geoff replied 1 year ago.

Here is the fault code overview.

Expert:  Geoff replied 1 year ago.

This is the trouble tree

Expert:  Geoff replied 1 year ago.

This illustration indicates how the check valve is tested with no more than 5 psi air.

Expert:  Geoff replied 1 year ago.

Please let me know if there is anything else you need assistance with.

Customer: replied 1 year ago.
now I need the procedure and the values for the blowby test please
Expert:  Geoff replied 1 year ago.

Sorry, I didn't see that you had posted a message. Do you still need

Expert:  Geoff replied 1 year ago.

this information?

Customer: replied 1 year ago.
on the trouble tree in 4a I belive it says to check the blowby and refers to service manual ISB CM 2150 service manual , bulletin(###) ###-####and procedure 014-010 in section 14
this appears to be the information I need
Expert:  Geoff replied 1 year ago.

Blowby Measurement Steps

Expert:  Geoff replied 1 year ago.

If I have adequately addressed your issue, please remember to leave feedback.

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