What it means
The signal from crankshaft position sensor B is above the expected level. This indicates a high signal condition; the cause may be in the sensor or its circuit.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Crankshaft position sensor B reports crankshaft rotation and position to the engine controller. This code sets when the signal is higher than expected, which can happen if the signal line is open or the wiring is shorted to a power source.
Common causes
Most likely first.
- Open signal line
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Hard starting or no start
- Engine stalling or rough running
- Power loss
How to diagnose it
- Check freeze-frame data and live engine-speed readings during cranking to see how sensor B's high signal relates to starting or running symptoms.
- Inspect sensor B's connector and harness for an open wire, corrosion, loose pins, or a pinched wire touching a power feed.
- Check the sensor mounting and visible tone wheel for damage or misalignment that could affect the signal.
- Use the wiring diagram to test sensor B's signal circuit for continuity and an unintended connection to battery positive, following the manufacturer's procedure.
- If wiring checks out, test sensor B's output and the controller input according to the manufacturer's specification.
Common fixes
- Repair an open or damaged sensor B signal wire.
- Separate and repair wiring that is pinched against a power source.
- Clean or repair corroded connector terminals and secure loose pins.
- Replace sensor B if it fails the specified output test with sound wiring.
Can I keep driving?
A high sensor B signal may make starting unreliable or cause stalling and power loss. If the engine runs unevenly or stalls, avoid driving it until the signal fault is repaired.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.