Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P051A Crankcase Pressure Sensor A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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. P051A is the sensor's general circuit fault. Ford uses it only for the digital SENT sensor, when the module receives invalid messages or signal patterns (together with U060E for lost communication); analogue sensors report P051B–P051D instead. It is checked continuously with 5 s to fault.

Likely causes

Connector or supply, ground or SENT signal wire open or corroded
Sensor electronics faulty
Oil or moisture in the connector
Engine module

Symptoms

  • Check engine light on
  • Usually no change in driving
  • Disconnection check P04DB suspended

Repair estimate

DifficultyEasyDIY possible
Parts and labour€40–200
Time0.3–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

crankcase pressure sensorsensor wiringengine control module

Related codes

P051BP051CP051DP051EP04DBP04E1

References: fordservicecontent.com, patents.google.com, law.cornell.edu.