App must be running to connect to the vehicle. It does not automatically start. Any other app that you use on the Toyota must also be installed and actively running on your phone or it will not work. The app only connects to the Toyota about 25% of the time or so. When it won't connect, it needs to be force stopped through "settings">"apps" on the phone. Usually takes 3-5 tries before it actually connects. None of the Toyota apps will work unless this app is actively running.