Error 40 may occur when you press and hold the bell button for a long time, or when you press it too many times in a row. It can also occur if water gets into the button.

Make sure your bike is updated to the latest firmware. Then, try resetting your bike: Press and hold the power button on the underside of the top tube for two seconds until you see the reset symbol on the Matrix Display. 

If this doesn’t work, the button might be stuck. Try these steps:

• Check if the button still makes the bell sound 
• Check if you can wake up the bike from sleep with the bell button 
• Check if you can unlock your bike using your back up code