OBD-II code · Powertrain (generic)

P051F PCV Filter Restriction

The pressure or flow sensor in the PCV path detects increased restriction across the oil-mist filter element. Once saturated with oil mist, the filter no longer passes blow-by gas, raising crankcase pressure and pushing oil past seals.

Is it safe to drive with P051F?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyPCV filter saturated with oil mist

Repair at a glance

Difficulty
Easy
DIY friendly
Often, with basic tools
Typical labour
0.3–1 h
Emissions test
Likely to fail
Parts involved
Pcv Filter, Crankcase Pressure Sensor A

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.