P051CCrankcase Pressure Sensor A Circuit Low
- 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. P051C means the signal of the analogue ratiometric sensor is too low – Ford sets it below 0.44 V for 5 s. Typical is a signal shorted to ground, an open or shorted 5 V reference, or an open signal line pulled down.
- What you may notice
- Check engine light on
- Usually no change in driving
- Disconnection check P04DB suspended
- Likely causes
- Likely5 V reference or signal line open or shorted to ground
- PossibleConnector corroded or oily
- PossibleSensor faulty
- Rare5 V reference pulled down by another sensor
- 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
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.