P051E
Crankcase Pressure Sensor A Circuit Intermittent/Erratic
Crankcase ventilation (PCV)
Generic OBD-II
High
What it means
P051E means the ECM has seen an intermittent, erratic signal from crankcase pressure sensor "A", which monitors pressure inside the crankcase as part of the ventilation (PCV) system. The engine usually runs normally, but the on-and-off signal typically points to a loose connector or chafed wiring — or occasionally a PCV problem disturbing the reading.
High
Can I keep driving? Usually drivable — the engine runs, but a crankcase-pressure fault can point to a PCV or ventilation problem, so have it diagnosed.
Common symptoms
What you'll notice
- Check-engine light on (may come and go)
- Usually no obvious change in how the engine runs
- Possible faint oil smell or minor oil consumption if PCV flow is disturbed
Common causes
Most likely first
- Intermittent fault in the crankcase pressure sensorLikely
- Loose, corroded, or backed-out sensor connectorCommon
- Chafed or intermittently shorting wiring in the circuitCommon
- PCV or crankcase ventilation issue affecting the sensor readingLess often
- Rarely, a failed ECMLess often
How to diagnose & fix
Work through it in order
- Wiggle-test the crankcase pressure sensor connector and harness while watching live data for dropouts.
- Inspect and clean the connector; repair any chafed or pinched wiring.
- Check the PCV system and hoses for leaks or blockage that could disturb crankcase pressure.
- Test the sensor signal against spec and replace it if erratic, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P051E?+
Generally yes, since it rarely changes how the car drives, but it can flag a PCV/ventilation issue, so get it checked before it worsens.
Can I just clear P051E?+
Because the fault is intermittent it will likely return until the loose connector, wiring, or PCV issue is found and fixed.
Related codes
Often seen with P051E
Read & clear P051E yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX