Does the Volvo heartbeat sensor (tells you if someone is in the car) work if the car isn't running?

Does the Volvo heartbeat sensor (tells you if someone is in the car) work if the car isn't running? This is indicated when you press a button on the Personal Car Communicator Key Volvo cars come with.|||Actually it ONLY works if the car is off and the alarm is set.|||Yes and you can get the information up to 100 meters away from the car.