You are trying to connect with the vehicle and get the message
"Can't access Bluetooth devices":
The message appears because the app is asking for the location permission (From Android M Google pushing the developers to request location permission to access Bluetooth devices.
You will find more information about that by pressing the following link: https://developer.android.com/about/versions/marshmallow/android-6.0-changes.html ).
To solve that follow the instructions (The settings menu could be different on your Android, it depends on the version):