Detailed guide for SPN 101 FMI 2
Back to top ↑What SPN 101 FMI 2 means
SPN 101 identifies crankcase pressure. FMI 2 indicates that the crankcase pressure sensor signal is erratic, implausible or outside the calibrated rational range.
Detroit GHG17 documentation describes this condition as a crankcase pressure sensor drift fault.
What to check first
Check for other active sensor circuit faults before diagnosing this code by itself.
Inspect the crankcase pressure sensor connector for corrosion, damaged pins, loose terminals or contamination.
Inspect the sensor harness for opens, shorts to ground, shorts to power or damaged wiring.
Verify the sensor supply, ground and signal circuits using the OEM wiring diagram and diagnostic procedure.
Important
FMI 2 does not automatically prove that actual crankcase pressure is mechanically excessive. The sensor signal and electrical circuit should be verified before replacing crankcase ventilation components.
Always confirm the procedure for the specific engine family and calibration.
Mechanic community notes for SPN 101 FMI 2
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