Crankcase Pressure Sensor
Measures pressure inside the crankcase directly, which catches far more than a sensor that only checks whether the breather hose is plugged in. A healthy engine runs its crankcase at a slight depression — a little below atmospheric — and that is what stops blow-by gas pushing oil out through the seals.
Watching that pressure detects several faults that otherwise have no sensor of their own: a blocked breather or oil separator, which lets pressure build; a torn separator diaphragm, which lets the intake pull far too hard; a split or disconnected hose, which brings the crankcase to atmospheric. And, over time, worn piston rings — because blow-by rises as an engine wears, and this sensor measures blow-by directly. It is one of the few sensors that gives early warning of engine wear rather than of a component failing.
The cheap sanity check is at rest: with the engine off the crankcase must be at atmospheric, and this sensor must agree with the barometric sensor.
It sits in oil mist by definition, since it measures the space oil vapour lives in — so oil wicking along the wires into its connector is its characteristic fault, and finding the source matters as much as cleaning the connector.
Also known as: crankcase vent pressure sensor, ccp sensor, blow-by pressure sensor, crankcase vacuum sensor
Referenced by 14 codes
Codes involving this component (14)
- P051B Crankcase Pressure Sensor A Circuit Range/Performance Moderate
- P051C Crankcase Pressure Sensor A Circuit Low Moderate
- P051D Crankcase Pressure Sensor A Circuit High Moderate
- P04E1 Crankcase Ventilation Hose Connection Sensor Circuit
- P04E3 Crankcase Ventilation Hose Connection Sensor Circuit High
- P04E4 Crankcase Ventilation Hose Connection Sensor Circuit Intermittent/Erratic
- P051A Crankcase Pressure Sensor A Circuit
- P051E Crankcase Pressure Sensor A Circuit Intermittent/Erratic
- P053E Crankcase Pressure Too High
- P2C32 Crankcase Pressure Sensor B Circuit
- P2C34 Crankcase Pressure Sensor B Circuit Low
- P2C35 Crankcase Pressure Sensor B Circuit High
- P2C36 Crankcase Pressure Sensor B Circuit Intermittent/Erratic
- U060E Lost Communication With Crankcase Pressure Sensor
Other components in Air Intake and Metering
- Intake Air Temperature Sensor 83
- Throttle Body 69
- Throttle Position Sensor 58
- Intake Manifold Tuning Valve 56
- Mass Air Flow Sensor 52
- Intake Manifold 51
- EGR Throttle Valve 38
- Throttle Actuator Motor 34
- PCV Valve 31
- Air Filter 30
- Manifold Absolute Pressure Sensor 29
- Crankcase Breather Hose 13
- Intake Air Heater 11
- Idle Air Control Valve 9
- Intake Air Oxygen Sensor 7
- Humidity Sensor 5
- Air Cleaner Inlet Actuator 3
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Working on this component
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about Crankcase Pressure Sensor.