Obdaryn

P051DCrankcase Pressure Sensor A Circuit High

  • Generic OBD-II code · Powertrain
  • Turns on the check-engine light
  • Matters for the ITP
  • Needs a drive cycle to confirm a fix
How the car detects it
The crankcase pressure sensor measures pressure in the crankcase ventilation (PCV) against atmosphere; Ford's EcoBoost engines use it for the disconnection check P04DB, which needs a sound sensor. P051D means the signal is too high – Ford sets it above 4.56 V for 5 s. Typical is a signal shorted to 5 V or battery voltage, an open sensor ground, or an open signal pulled up. A real excess pressure in the crankcase does not set P051D.
What you may notice
  • Check engine light on
  • Usually no change in driving
  • Disconnection check P04DB suspended
Likely causes
  • LikelySensor ground open
  • PossibleSignal line shorted to positive
  • PossibleSensor faulty
  • RareEngine module
Inspection (ITP)
Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
Repair
Easy · Often possible to do yourself.Typical cost: €40 – €200

Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.