Error 16 indicates a defect or connection problem with your battery.
Please try these steps to fix it:
Step 1: Firmware update
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.
Step 2: Reset
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.