Error 25 is Brake Sensor Connection Error  

Connection error between the brakes and the bike itself. Brakes will still manually work, but not they are not in sync with the speedometer and LCD screen.

The Fix:

1. Make sure all cables are intact and plugged into the appropriate connection. 

2. Clean the sensors on the actual handbrakes, You can do so with some compressed air or some electronics part cleaner. Bike may have been turned on with brakes applied. Turn the bike off, make sure brakes are not applied, turn the bike back on. If there is no resolution, unplug each brake by itself and restart the bike for each brake to see which brake is causing the error. If error persists after both have been unplugged, try a new controller.