P0394
Camshaft Position Sensor B Circuit Intermittent Bank 2
Ignition / cam & crank
Generic OBD-II
High
What it means
P0394 means the second camshaft position sensor on bank 2 is dropping out intermittently. The ECM uses cam position to time fuel and spark, so a signal that comes and goes — usually from chafed wiring, a loose connector, or a marginal sensor — can cause occasional stalling, hard starting, and rough running that's hard to catch.
High
Can I keep driving? Runs normally most of the time but can stall, hesitate, or be hard to start intermittently; have the wiring and sensor checked before relying on it.
Common symptoms
What you'll notice
- Check-engine light on
- Intermittent stalling or hard starting
- Occasional hesitation or rough running
- Reduced power at times
Common causes
Most likely first
- Intermittent fault in the camshaft position sensor 'B' (bank 2)Likely
- Chafed, loose, or intermittently shorting wiring in the circuitCommon
- Loose or corroded connector at the sensorCommon
- Debris on the sensor tip or a damaged reluctor wheelLess often
- Failed ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to capture the conditions when the fault appears.
- Wiggle-test the cam sensor 'B' connector and harness while watching live data for signal dropouts.
- Inspect the wiring for chafing, especially near hot or moving components.
- Clean the sensor tip and check the tone wheel for damage.
- Replace the sensor if the signal drops out intermittently. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0394?+
Use caution. An intermittent cam signal can cause sudden stalling or a no-start at the worst time. Diagnose it before depending on the vehicle.
Can I just clear P0394?+
It returns the next time the signal drops out. Because the fault is intermittent, focus on wiring and connectors, repair the cause, then clear and re-test.
Related codes
Often seen with P0394
Read & clear P0394 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