Cummins ISX15 crankcase pressure

Did you pull the loom back and check the wiring going to the sensor? Mine rubbed through a few inches from the plug, cummins sells a pigtail to rewire it.

What year is this truck?

 

Did it come on while you were pulling a hill?

 

If your wiring is good then cummins may need to do a blowby test and check and see if the turbo is boosting into the crankcase.

 

If you have excessive blowby then your piston rings could be worn or broken or your liners are worn. Those things usually come with increased oil consumption. Are you using alot more oil than usual?

Air compressors can go bad and pump air into the crankcase but it shouldn't be enough to trip a code, especially with a free flowing crankcase breather filter.

If the turbo is boosting into the crankcase then the seals in the turbo are bad and you need a new one.

With the engine warm and running, take off the oil fill cap. Is there alot of blowby? If there is...... does it puff like a Choo Choo train?

If you wanna save some money and check yourself for real cheap, watch this video on how to check blowby.



To test the turbo. Do the blowby test and mark how high the water goes, shut off the truck and disconnect the turbo oil return line and put it in a bucket. Then redo the blowby test, if your blowby level is less.... your turbo is bad.

Keep in mind that oil will be going into the bucket from the engine so don't let it run forever but losing a galon or so during the test doesn't hurt nothing, your engine has 10+ gallons in it.

 

No, I'd say that's normal. A little high but nothing to cry home about.