E21 Current Error

The motor current output has exceeded the controller's current limit, causing the controller to shut down to protect against overheating. This usually happens during long periods of climbing with maximum pedal assist turned on. To clear the error, stop riding and power off the bike. Let the bike cool down for 2 minutes to see if the error code disappears upon reboot. The motor or controller could be damaged, such as from a worn cable or poor connection, either part may need to be replaced. If the error code persists, ensure there is no damage or loose connections with the motor or the controller. 

E21 FLOW CHART