Failed crankshaft position sensor 'B' due to heat, age, or contamination; Damaged or corroded wiring harness and connector at the sensor; Metal debris or a damaged reluctor wheel interfering with the sensor signal; Poor electrical connection at the powertrain control module; Open or short circuit in the sensor signal or ground circuit; Mechanical wear in the sensor mounting or air gap misalignment

DTC codes / P03xx · Ignition system and misfire / P0385

P0385Crankshaft Position Sensor 'B' Circuit

Q: What does code P0385 mean?

Crankshaft Position Sensor 'B' Circuit. P0385 indicates that the powertrain control module has detected an electrical fault in the circuit for crankshaft position sensor 'B', which is the second crank sensor on engines that use two for redundancy or for different signal ranges. The computer monitors the signal voltage and timing from this sensor and sets the code when the signal is missing, erratic, or outside the expected range during engine operation.

P0385 indicates that the powertrain control module has detected an electrical fault in the circuit for crankshaft position sensor 'B', which is the second crank sensor on engines that use two for redundancy or for different signal ranges. The computer monitors the signal voltage and timing from this sensor and sets the code when the signal is missing, erratic, or outside the expected range during engine operation.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Intermittent engine stalling or a sudden loss of power while driving
Difficulty starting or a no-start condition, especially when the engine is hot
Rough running or misfiring due to inaccurate ignition timing
A tachometer that reads erratically or drops to zero intermittently

Common causes, most likely first

Failed crankshaft position sensor 'B' due to heat, age, or contamination
Damaged or corroded wiring harness and connector at the sensor
Metal debris or a damaged reluctor wheel interfering with the sensor signal
Poor electrical connection at the powertrain control module
Open or short circuit in the sensor signal or ground circuit
Mechanical wear in the sensor mounting or air gap misalignment

How to diagnose and fix it

Perform a visual inspection of the sensor, connector, and wiring for damage or debris
Check for technical service bulletins or known issues for the specific vehicle
Measure sensor resistance and compare to specifications, then check for signal output with a scope
Verify the integrity of the sensor ground and signal circuits with a multimeter
Inspect the reluctor wheel for cracks, missing teeth, or excessive runout
Replace the crankshaft position sensor 'B' if tests indicate failure
Clear the code and perform a road test to confirm the repair

What most technicians overlook with P0385

A failing sensor 'B' often does not prevent the engine from running because sensor 'A' provides a backup signal, so the only clue may be the stored code.
Debris stuck to the magnetic tip of the sensor can mimic an electrical failure and is frequently missed during diagnosis.
Wiring harness chafing near hot exhaust components or sharp brackets is a common cause that visual inspection alone may not reveal.
The code can be set by a faulty powertrain control module, but this is rare and should only be suspected after all other possibilities are ruled out.
After replacing the sensor, the crankshaft position variation learn procedure may be required on some vehicles to prevent a repeat code.

Can I keep driving with P0385?

It is generally safe to drive with P0385 if the engine runs normally, but avoid aggressive acceleration or long trips until the fault is repaired because a complete sensor failure could cause sudden stalling. If the engine stalls or loses power, pull over safely and arrange a tow.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.