Error 18 means that the battery wasn’t able to turn on.
Try these steps to fix it:
1. Make sure your bike has the latest firmware installed – you can check this on your app settings screen. If there is a new version available, install it.
2. Reset 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. Press either handlebar button to power the bike on. If the bike is locked, use one of the 3 ways to unlock your bike.
If you’re still having problems, contact customer support.