If your camera has a screen, you can know its status by the left-central icon as per the below pic, the icon will change to a car when it switches back to normal mode,
If your camera support voice notification but has no screen, you will hear a voice notification “Parking recording, started” when your car engine switches off, and you will hear "Recording, one/two/three channel started" when you restart the engine.
Click Videos more videos of hardwire installation
Click menu functions for more tips on auto-event detection
Click for External battery pack for more tips on the battery pack