What it means
The vehicle speed sensor B signal is outside the expected range or does not match expected vehicle speed.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Vehicle speed sensor B reports speed to a control module, with its exact location and function depending on the vehicle. This code sets when the sensor B signal is implausible or outside the expected operating range, including a mismatch with other speed information.
Common causes
Most likely first.
- Faulty vehicle speed sensor B
- Damaged wiring or connector
- Sensor element aged beyond calibration window
Symptoms
- Speedometer may read inaccurately or fluctuate
- Transmission shifting may be affected
- Cruise control may not work
- ABS or traction-control warning light may come on
How to diagnose it
- Record freeze-frame data and check related ABS, transmission, and speed-sensor codes to see when the sensor B reading became implausible.
- Compare live sensor B speed with other available wheel or vehicle speed readings while driving steadily in a safe area.
- Inspect sensor B, its connector, wiring, mounting, and target for damage, contamination, corrosion, or excessive movement.
- Check the sensor B supply, ground, and signal quality as applicable, comparing results with the manufacturer's specification.
- If the circuit and target appear sound, test sensor B across operating conditions to determine whether its output drops out or remains out of range.
Common fixes
- Repair damaged sensor B wiring or a loose connection.
- Clean contamination from the sensor B connector or target and secure the connector.
- Correct damaged or misaligned sensor B mounting or target components.
- Replace sensor B if its signal remains outside the expected range after the circuit and target are checked.
Can I keep driving?
Use caution because an implausible sensor B speed signal can disrupt shifting, cruise control, or stability and braking assistance. Avoid cruise control and arrange diagnosis soon, especially if ABS or traction-control warnings are present.
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.