OBD
P051B
Crankcase Pressure Sensor A Circuit Range/Performance
What it means
P051B means Crankcase Pressure Sensor A Circuit Range/Performance.
Where it lives
For P051B, start at the sensor the description names.
Check these first
- A crankcase pressure sensor A reading outside its range
- A failed crankcase pressure sensor A
- Excessive blow by from worn rings
- A clogged crankcase ventilation system
What to do next
- Read the crankcase pressure sensor A on a scan tool
- Compare the reading to the expected crankcase pressure
- Check the crankcase ventilation system for a clog
- Run a compression test if blow by is suspected
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.