P051A code meaning
Crankcase Pressure Sensor A Circuit
Powertrain system Generic code P05xx codes Check engine light
What P051A means
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.
P051A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P051A
- Check engine light on
- Usually no change in driving
- Disconnection check P04DB suspended
Common causes of P051A
- Most likelyConnector or supply, ground or SENT signal wire open or corroded
- PossibleSensor electronics faulty
- PossibleOil or moisture in the connector
- Less likelyEngine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Crankcase pressure sensorSensor wiringEngine control module
What each part of P051A means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 1A | The exact fault in that area. |
What to do next
- Note P051A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P051A
What does P051A mean?
P051A means "Crankcase Pressure Sensor A Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P051A?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P051A fail an emissions test?
Yes, it can. P051A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P051A to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P051A clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.