parking sensor

Hello, I have a problem with my parking sensor. When reverse gear is engaged, the parking sensor sounds first, followed by a second beep. In the instruction manual, this indicates a warning of the groove of a fault. I wonder what could be the fault? what should I do?

MAY BE PROBLEM IN THE DEVICE ... HELP HARD HERE MORE HEALTHY I LOVE YOU TO LOOK AT THE AUTO ELECTRICIAN ,,,

Perhaps it is a sensor malfunction, the sensors are disconnected and look at them, whichever is interrupted.