RideFixerBafang error code
Bafang error 21: Speed sensor fault
Medium severity Service soon
Can I ride home with this error?
Ride with caution. Safe to pedal without assist.
What it means
The speed sensor or its spoke magnet is not working, so the bike cannot measure speed. Assist is limited or stopped because the speed limit cannot be applied.
Likely causes
- Spoke magnet moved or missing
- Sensor too far from the magnet
- Loose or damaged sensor cable
Symptoms
- Code 21 shows
- Speed reads 0 or wrong
- No or reduced assist
How to fix it
- Switch the bike off, wait 10 seconds and switch it on again.
- Check the spoke magnet lines up with the speed sensor and the gap is 10–20 mm (as Bafang's manual states).
- Check the speed sensor cable and connector.
- If the code stays, your dealer can check the sensor signal with the Bafang BESST tool or replace the sensor.
How urgent is it?
Assist and the legal speed cut-off need a working speed sensor.
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