P0385
Crankshaft Position Sensor B Circuit
Ignition / engine timing
Generic OBD-II
High
What it means
P0385 flags a fault in the "B" crankshaft position sensor circuit. The crank sensor tells the ECM engine speed and piston position, which is essential for spark and fuel timing, so problems here can cause hard starting, stalling, or a no-start. The cause is usually the sensor, its wiring, or the connector.
High
Can I keep driving? Risky — the crank sensor is central to spark and fuel timing, so this can cause stalling or a no-start; drive minimally until repaired.
Common symptoms
What you'll notice
- Check-engine light on
- Hard starting or intermittent no-start
- Stalling or cutting out while driving
- Hesitation and reduced power
Common causes
Most likely first
- Failed crankshaft position sensor BLikely
- Signal wire open, shorted, or chafed in the circuitCommon
- Loose or corroded connector at the sensorCommon
- Damaged crankshaft reluctor/tone ringLess often
- ECM fault (rare — confirm sensor and wiring first)Less often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame data to confirm the fault is the crank sensor B circuit.
- Inspect the connector and wiring for damage, heat, oil, or corrosion.
- Back-probe the sensor for supply, ground, and a clean signal while cranking.
- Check the sensor air gap and the crank reluctor ring for cracks or debris.
- Replace the crank position sensor if it fails testing with good wiring. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0385?+
No — a crank-sensor fault can shut the engine off without warning and leave you unable to restart. Get it diagnosed promptly.
Can I just clear P0385?+
It returns as soon as the ECM re-tests the circuit and won't stop stalling. The fault has to be traced and repaired.
Related codes
Often seen with P0385
Read & clear P0385 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