P0389
Crankshaft Position Sensor B Circuit Intermittent
Ignition / engine timing
Generic OBD-II
High
What it means
P0389 means the ECM sees an intermittent signal from crankshaft position sensor B — the sensor that tracks engine speed and position to time spark and fuel. Because the fault comes and goes, the engine may run fine one moment and stall or refuse to start the next, which makes it important to trace the wiring or sensor promptly.
High
Can I keep driving? It may run but can cut out or refuse to start without warning — treat an intermittent crank-sensor fault as urgent.
Common symptoms
What you'll notice
- Check-engine light on
- Intermittent stalling or cutting out
- Hard starting or intermittent no-start
- Hesitation, surging, or a misfire
Common causes
Most likely first
- Faulty crankshaft position sensor B or an intermittent connectionLikely
- Chafed, loose, or corroded wiring in the sensor circuitCommon
- Damaged reluctor/tone ring or missing teethCommon
- Heat-related sensor dropout (fails when hot, recovers when cool)Less often
- Faulty ECM (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is the crankshaft sensor B circuit.
- Wiggle-test and inspect the sensor connector and harness for intermittent contact or chafing.
- Check the signal, power, and ground at the sensor, ideally while the fault is present or the engine is hot.
- Inspect the reluctor ring for damaged or missing teeth and debris.
- If the circuit and ring are good, replace the crankshaft position sensor. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0389?+
Risky — an intermittent crank signal can stall the engine at any moment or leave it unable to restart. Fix it before relying on the vehicle.
Can I just clear P0389?+
It will return when the intermittent fault reappears. Clearing won't stop a stall if the signal keeps dropping out.
Related codes
Often seen with P0389
Read & clear P0389 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