21 Code
Check M2S 21 e-Bike Error Code :
Error Type:
Voltage Current Error
Source Of Error
The battery is not supplying the required voltage to power the display and motor. This can be caused by working the internal controller, motor, and/or battery too hard in some cases (long extended climbs with the rider not pedaling hard enough).
E-Bike Error Code 21 :
Speed Sensor Error
Steps To Resolve
1) Check the distance between your speed sensor and magnet. An error 21 is typically a simple fix and is due to improper installation and placement of the magnet in regards to the speed sensor. The magnet must be installed within 1-2mm of the speed sensor.
2) Check the path of travel of your magnet in relation to your speed sensor. The path of magnet travel must be directly perpendicular to the orientation of the speed sensor in order to properly operate.
3) Check the location of your speed sensor in relation to the rotation of your bike's tire. Our recommendation is to install the sensor as far away from the center of the wheel as possible in order to help make sure that the magnet path of travel is as perpendicular to the speed as possible.
4) Make sure that the Speed Sensor Cable was NOT yanked and pulled out of the Controller housing during installation