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Maladjusted's avatar
Maladjusted
Explorer
May 25, 2013

Cummins ISB 6.7 340 HP crankcase pressure sensor

Tripped a check engine light on our way down to OBX on Friday. Called Cummins and diagnosed the engine code as a crankcase pressure sensor... Again. This is the second time in 500 miles. I had the same sensor trip a check engine light on our way home from delivery.

Anyone else having this sensor go bad?

Mal
  • 2007 and later engine I am guessing? What was the code? Is it a sensor out of range code or "Crankcase Pressure - Data Valid but Above Normal Operational Range" code?

    If it is the "Crankcase Pressure - Data Valid but Above Normal Operational Range" you probably need to service the crankcase breather filter.

    If it is out of range, you have a bad sensor or an intermittent wiring fault.

    Doug
  • This is the code pulled from the driver information center...

    SPN 101 FMI 2 OC 1

    I contacted Cummins customer service... Same error I got on the way home from delivery. Crankcase pressure sensor, intermittent signal.

    Yes...2013 Coach.

    Don't know why I've now smoked two Crankcase Pressure sensors on this motor in 500 miles.

    Mal
  • Maladjusted wrote:
    This is the code pulled from the driver information center...

    SPN 101 FMI 2 OC 1

    I contacted Cummins customer service... Same error I got on the way home from delivery. Crankcase pressure sensor, intermittent signal.

    Yes...2013 Coach.

    Don't know why I've now smoked two Crankcase Pressure sensors on this motor in 500 miles.

    Mal

    The code you mentioned represents "Crankcase Pressure - Data Erratic, Intermittent, or Incorrect". I agree that it is most likely a sensor. Hopefully its not a problem with the engine harness.

    We don't seem to have many problems with crankcase pressure sensors. Ours are 2011 and older engines. Given that you have gone through two of them, there is a chance that you may have something more going on.
  • Worst case of a high pressure in the crank case I have heard of was caused by blow by at the valve stems and cylinder liners. The real cause was that the engine was "dusted" due to not securing the air intake and air got into the engine with out going through the air filter. Dust "sanded" and increased all the tolerances causing pressure in the crank case. The dirty air also "ate up" the turbo blades. This was on a brand new coach that came from the factory with the loose air intake hose. A big problem that no one wanted to stand behind as it was a "maintenance issue". It was finally resolved and fixed but was a real mess. Suggest you do whatever you must to get the problem identified and resolved. The bill to fix the one I know about was about $30,000.
  • imgoin4it wrote:
    Worst case of a high pressure in the crank case I have heard of was caused by blow by at the valve stems and cylinder liners. The real cause was that the engine was "dusted" due to not securing the air intake and air got into the engine with out going through the air filter. Dust "sanded" and increased all the tolerances causing pressure in the crank case. The dirty air also "ate up" the turbo blades. This was on a brand new coach that came from the factory with the loose air intake hose. A big problem that no one wanted to stand behind as it was a "maintenance issue". It was finally resolved and fixed but was a real mess. Suggest you do whatever you must to get the problem identified and resolved. The bill to fix the one I know about was about $30,000.

    With internal engine problems you would see a "Crankcase Pressure - Data Valid but Above Normal Operational Range". the op is seeing invalid data from the sensor so there is no indication that he has an internal engine problem.

    When I have seen problems with either rings or valve guides, you will have a "Crankcase Pressure - Data Valid but Above Normal Operational Range" code. Servicing the crankcase breather filer will usually bring the crankcase pressure back into the normal range. As an internal problem develops, you will see the crankcase breather filter needing to be serviced more frequently.

    Oil analysis is by far the best way to detect an intake leak and prevent damage to the engine.
  • Ivylog's avatar
    Ivylog
    Explorer III
    It's new. 2013 = warranty. He just got it. Take it to Cummins.
  • One other thing the friend who had the problem I referenced above was that he had the codes read and checked several times at Cummins authorized locations. at least one of them said they could not replicate the codes. He was later told by the Cummins shop that did the repair that smaller locations will sometimes "not find" or properly identify codes as they do not want to take on the job. It is just easier to not find anything and send folks on down the road.
  • Update:

    Got it back from Cummins, the crankcase breather housing was cracked. Probably cracked from the factory, just took a few heat cycles to really show itself. Covered under warranty.

    Hopefully we can close the book on this issue.

    Now, back to Cummins with a smoked compressor for the dash A/C!!

    Mal