What it means
A general electrical fault on crankshaft position sensor B — second crank sensor used as backup or for advanced timing models on some engines.
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, which uses that information for timing and engine operation. This code indicates a general electrical fault in sensor B's circuit, without specifying whether the signal is too high, too low, or intermittent.
Common causes
Most likely first.
- Crankshaft position sensor B failure
- Damaged, loose, or corroded sensor wiring or connector
- Damaged or misaligned reluctor/tone wheel
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 data during cranking to see whether the controller receives a usable signal from crankshaft sensor B.
- Inspect sensor B's connector and wiring for looseness, corrosion, damage, or routing that could expose it to heat or rubbing.
- Check the sensor mounting and the visible reluctor or tone wheel for looseness, damage, debris, or misalignment.
- Use the wiring diagram to test sensor B's supply, ground, and signal circuit as applicable to the sensor type, following the manufacturer's procedure.
- If the circuit checks out, test sensor B and compare its output with the manufacturer's specification before considering a controller fault.
Common fixes
- Reconnect or secure a loose sensor B connector.
- Repair damaged or corroded sensor B wiring and connector terminals.
- Correct a loose sensor mounting or repair a damaged or misaligned reluctor wheel.
- Replace crankshaft position sensor B if its output fails the specified test.
Can I keep driving?
Starting, stalling, or power loss can occur if the controller cannot use sensor B's signal. Avoid driving if the engine stalls or will not restart reliably, since loss of engine control can leave you without power unexpectedly.
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.