What it means
The ECM detects a circuit fault on the crankcase pressure sensor b circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Crankcase pressure sensor B reports pressure in the engine crankcase to the ECM, which uses the signal to assess crankcase ventilation and engine operation. This circuit code means the ECM has detected an electrical fault in sensor B's circuit, so it cannot rely on that signal.
Common causes
Most likely first.
- Sensor failed
- Wiring or connector fault
Symptoms
- Check-engine light
- Rough or uneven idle
- Lower fuel economy
How to diagnose it
- Check freeze-frame data and live sensor readings to note when the fault appears and whether sensor B reports a fixed or implausible value.
- Use the vehicle's service information to locate crankcase pressure sensor B, then inspect its connector and harness for loose fit, corrosion, oil intrusion, or damage.
- Check the sensor B power, ground, and signal circuit continuity and for shorts, following the manufacturer's wiring diagram and specifications.
- If wiring and connections are sound, test sensor B according to the manufacturer's procedure and compare its output with the specified response.
- Repair the fault, clear the code, and confirm sensor B readings respond plausibly at idle and during a brief engine-speed change.
Common fixes
- Reconnect or clean and secure the sensor B connector.
- Repair damaged wiring or a poor ground in the sensor B circuit.
- Replace crankcase pressure sensor B if it fails its specified circuit test.
- Clear the code and verify the signal after the repair.
Can I keep driving?
If the engine runs smoothly, a short gentle drive to a repair location is generally reasonable, but avoid prolonged driving if idle quality or fuel economy worsens. Have the fault addressed because unreliable crankcase pressure feedback can affect engine control.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.