P0386 Crankshaft Position Sensor B Circuit Range/Performance

P0386 points to a range or performance problem in Crankshaft Position Sensor B circuit. The signal is present but not plausible for engine speed or position.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not condemn the sensor before checking reluctor condition and signal alignment with the other position inputs.

Symptoms of P0386

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0386

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Compare crank B signal quality, crank A agreement, cam-crank sync, freeze-frame RPM, startup behavior, and related correlation codes.
Inspect sensor mounting, air gap, reluctor damage, crank end play, wiring resistance, connector condition, grounds, and electrical noise sources.
Check whether the signal becomes implausible only during cranking, high RPM, heat soak, vibration, or load.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.