XC 60 PDC (Park Distance Control) failed without error message

Hello, today I had a sudden failure of the PDC without any fault message or similar in the display. When starting the car the PDC worked while parking, then the car was moved about 50 km and then when parking it had said goodbye without any hint for the driver. I did not even notice it at all, only then wondered at the rear camera that the yellow and red squares for the distance warning were missing in the picture. And since w ar i almost drove with the rear to the wall :- ( Luckily I didn’t touch it. In any case I got out then, I looked if the sensors are particularly dirty or similar. But nothing like that. I turned off the car, after 5 minutes turned on and PDC was back (without having cleaned anything before). Now I ask myself, since the search in the forum did not deliver a corresponding hit, if you had the problem already (MY 2013). e it is especially stupid that when the PDC fails, a warning message does not even appear in the display!!! Although I park mainly on view and with mirrors, but at home this is such a standardized action that you already rely largely on the beeping and especially in the dark do not look back through the tinted rear window in the dark after the distance. Thank you for your hints