Damaged, contaminated or poorly connected wiring or connector to the crankshaft sensor (chafing, corrosion, heat damage, loose pins); Faulty crankshaft position sensor producing a weak, noisy or erratic signal; Sensor loose in its mounting, wrong air gap, or metal debris on the sensor tip; Damaged or dirty reluctor (trigger) wheel, or missing or bent teeth; Timing correlation fault between crankshaft and camshaft, such as a stretched chain, worn belt or jumped timing; Low battery voltage or poor power or earth supply to the sensor or control unit; Fault inside the engine control unit.

P0386

Crankshaft Position Sensor B Circuit Range/Performance.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
3: AreaIgnition system or misfire
86: FaultThe specific fault in that area

What it means

P0386 is the generic code for a range or performance fault in the crankshaft position sensor 'B' circuit. The engine control unit has seen a signal from this sensor that is implausible or out of expected limits, for example a signal that does not match the camshaft position signal or a pattern that does not fit engine speed. Which sensor counts as 'B' and how the fault is detected depends on the make, model and engine.

Symptoms

Engine cranks but is slow to start or fails to start
Intermittent misfires or rough running
Hesitation or loss of power under acceleration
Engine stalling, often when warm
Rev counter flickering or dropping to zero
Check engine light on, possibly with limp mode

Possible causes

Damaged, contaminated or poorly connected wiring or connector to the crankshaft sensor (chafing, corrosion, heat damage, loose pins)likely
Faulty crankshaft position sensor producing a weak, noisy or erratic signallikely
Sensor loose in its mounting, wrong air gap, or metal debris on the sensor tippossible
Damaged or dirty reluctor (trigger) wheel, or missing or bent teethpossible
Timing correlation fault between crankshaft and camshaft, such as a stretched chain, worn belt or jumped timingpossible
Low battery voltage or poor power or earth supply to the sensor or control unitpossible
Fault inside the engine control unitrare

How to diagnose

Read all stored codes and freeze frame data, noting engine speed, temperature and load when the fault set, and check for related camshaft or misfire codes
Visually inspect the crankshaft sensor wiring and connector for chafing, oil contamination, heat damage, corrosion and tight pin fit
Check battery condition and charging voltage, and check the sensor's supply and earth circuits for correct readings against the manufacturer's data
Remove the sensor and inspect its tip and mounting for debris, damage, and correct seating or spacer
Inspect the reluctor wheel through the sensor aperture where possible for damage, dirt or missing teeth
Compare live crankshaft and camshaft signals using a scope or live data, looking for dropouts, noise or incorrect correlation
Check mechanical timing against the manufacturer's marks, especially if the chain or belt has high mileage or history of work
Test the sensor resistance or output against the manufacturer's specification, as the sensor type varies by model

How to fix

Repair or replace damaged wiring and clean or replace the faulty connector terminals
Replace the crankshaft position sensor with a correct specification part and tighten to the specified torque
Clean debris from the sensor and mounting area and correct the fitting or air gap
Repair or replace a damaged reluctor wheel or the component it is part of, as the design depends on the engine
Correct the engine timing and replace worn chain, belt or tensioners as required
Restore proper battery and earth condition, and only consider control unit repair or replacement once all other causes are ruled out

Can I keep driving?

High severity

Avoid driving until the fault is diagnosed, as the engine may stall without warning, which is unsafe in traffic. If timing correlation is suspect, continued running risks serious engine damage.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.