P0393
Camshaft Position Sensor B Circuit High Bank 2
Ignition / camshaft position
Generic OBD-II
High
What it means
P0393 means the computer sees an abnormally high voltage on the camshaft position sensor B circuit for bank 2. The cam signal helps time fuel and spark, so a bad signal can cause hard starting, rough running, or stalling — and on some vehicles a no-start. It most often traces to the sensor, a wiring short-to-voltage or open, or the reluctor ring.
High
Can I keep driving? Often driveable but the engine may run rough, hesitate, or be hard to start; on some vehicles a cam-signal fault can cause stalling or a no-start, so repair soon.
Common symptoms
What you'll notice
- Check-engine light on
- Hard starting or extended cranking
- Rough idle, hesitation, or occasional stalling
- Reduced power and fuel economy
Common causes
Most likely first
- Faulty camshaft position sensor B (bank 2)Likely
- Signal wire shorted to voltage or an open causing a high readingCommon
- Loose or corroded connector at the sensorCommon
- Damaged reluctor/tone ring or excessive sensor air gapLess often
- Failed engine control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm it's the bank 2 camshaft sensor B, circuit high.
- Inspect the sensor connector and wiring for a short to voltage, an open, or corrosion.
- Check the sensor's reference voltage, ground, and signal, and verify correct mounting and air gap.
- Inspect the reluctor ring; compare cam and crank signals for correlation with a scan tool.
- Replace the sensor if the signal stays high with good wiring. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0393?+
Short trips are usually possible, but the engine may stall or be hard to start. Have it diagnosed before relying on the vehicle.
Can I just clear P0393?+
You can, but it returns until the camshaft sensor or its circuit is repaired.
Related codes
Often seen with P0393
Read & clear P0393 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