Speed Sensor Error
Error 21 typically indicates a problem with the speed sensor system on your Bafang mid-drive electric bike. The speed sensor is crucial for determining the bike's speed and providing the appropriate level of electric assistance. When this error occurs, it can lead to inaccurate speed readings, inconsistent motor support, or even a complete loss of motor assistance.
Troubleshooting Steps
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Safety First: Ensure the electric bike is turned off and place the bike on a stable and level surface.
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Visual Inspection: Carefully inspect the speed sensor and its wiring for any visible damage, loose connections, or signs of wear. Ensure the sensor is properly aligned and free from obstructions.
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Magnet Alignment: Verify that the magnet on the wheel spoke is properly aligned with the speed sensor. A misaligned magnet can trigger Error 21. Adjust it if necessary.
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Test the Bike: After each step, turn on the bike and take it for a test ride. Pay attention to how the bike responds to throttle input and monitor the speed readings on the display.
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Check Magnet Condition: Examine the condition of the magnet on the wheel spoke. If it's damaged or worn, replace it with a new one to ensure accurate speed readings.
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Controller Reset: Some speed sensor errors can be resolved by resetting the controller. Turn off the bike, disconnect the battery, wait a few minutes, reconnect the battery, and turn the bike back on. Test the speed sensor again.
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Professional Assistance: If you're unable to resolve the issue on your own or if the problem persists, contact a certified electric bike technician or QuietKat Support for advanced diagnostics and repairs. If you are still within your warranty period, or have the Extend warranty, this will be covered. If you are outside of your warranty period, we will send you a quote for the replacement part(s).
Electrical Components Diagram for Mid-Drive Bikes:
