Can you keep driving?
Can you keep driving?
Stop driving if any of these apply
- !The vehicle suddenly runs much worse, loses power sharply, or the check-engine light starts flashing.
- !There is a strong smell, smoke, overheating, or any symptom that suggests a real-time safety problem rather than a stored code alone.
What to check first
Step-by-step checks
- 1
Free - no tools
Check whether the engine has a hard-start, stall, or rough-run symptom with the code
- 2
Free - no tools
Inspect the sensor connector and harness for oil, heat, or abrasion damage
- 3
Basic tool needed
Look for related crankshaft, camshaft, or misfire codes that may help with diagnosis
- 4
Basic tool needed
If scan data is available, compare crank signal stability with engine RPM behavior while the fault occurs
- 5
Basic tool needed
Notice whether the code appeared after timing work or sensor replacement
If the code returns
- -If the signal drops when the harness is moved, wiring or connector repair becomes more likely.
- -If the signal is unstable only when hot, heat-related sensor failure moves up the list.
- -If the code returns after connector repair, recheck sensor fit and wiring routing.
Background
What this code means
P0389 is a generic OBD-II code for an intermittent crankshaft position sensor B signal.
That usually means the signal is dropping out under vibration, heat, or load. The sensor, wiring, connector, or tone wheel can all be involved.
Diagnosis
Common causes
Loose crankshaft position sensor B connector
A loose connector can make the signal drop in and out.
Wiring damage or corrosion
Heat, vibration, or contamination can make the signal intermittent.
Failing crankshaft position sensor B
The sensor may work some of the time and then drop out.
Damaged tone wheel
A distorted reference pattern can look intermittent to the controller.
Avoid these mistakes
What not to do
- xDo not replace the ECU first if the sensor or tone wheel is visibly damaged.
- xDo not ignore intermittent stalling or no-start symptoms that line up with the code.
Parts
Parts that may need replacing
See also
Related OBD codes
Source notes
Generic OBD-II (SAE J1979 / ISO 15031-5). P0389 was seeded from dtcdb and then expanded around crankshaft position sensor B intermittent faults, with emphasis on sensor, wiring, and tone-wheel checks.
This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.
This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.
Last reviewed: 2026-04-10
Reference: Open reference