parking assistance system faulty

I have been getting this error for 1 week. The parking sensor has been working once in a while and giving this error once in a while. What could be the problem? By the way, I also noticed that the spare wheel was full of water, could it have something to do with it?

Sensors may be wet or the sensor brain

Just like our teacher friend said, one of the sensors may be malfunctioning or brain impaired. But first, find out where the water comes from, or you may experience the same problem.

The sockets that entered the brain dismantled the wet brain, and I installed it. I went to the body shop and removed the rear bumper. The corner of the body where the airing is installed is slightly in. We poured water, water was coming from there, I had a silicone. I put on the brain, the problem is solved.