Detailed guide for SPN 179 FMI 4
Back to top ↑Crankcase pressure signals tell the ECM how well combustion seals are holding. Low indicates ventilation problems that often cause smoke or rough idle.
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Share ↓SPN 179 FMI 4Severity: Warning
SPN 179 FMI 4: Crankcase pressure low – ventilation concern
Quick Answer
Crankcase pressure low – ventilation concern
Code
SPN 179 FMI 4
Severity
Warning
Applies to
Check OEM application
Can I drive?
Driving suitability is not established by this code alone.
Common Symptoms
- Oil consumption
- Blow-by increase
- Idle roughness
Likely Causes
- Crankcase ventilation fault
- PCV valve stuck
- Filter restriction
Common Fixes
- Check crankcase breather
- Clean/replace PCV
- Test system for restriction
Full technical sections↓
What does SPN 179 FMI 4 mean?
Back to top ↑Crankcase pressure low – ventilation concern
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