Needs: a BLE OBD-II dongle (e.g. Veepeak BLE+, Vgate iCar Pro BLE). Classic Bluetooth ELM327 dongles can't talk to browsers.
Works in: Chrome / Edge on Android, Windows, macOS.
iPhone: Safari has no Bluetooth API — open this page in the free WebBLE app instead, or use demo mode.
Ignition must be ON (engine can stay off for most readings).