Installed a PC5 the other day. The 02 connector by the voltage regulator is just there unconnected and open to any debris that can clog it up. Thinking ahead if I ever needed to reconnect the sensors I would like to keep the connectors working.
Is there a plug cap available I could put in the connector? Maybe also plugging the one under the seat is a good idea also.

 

Put some heat shrink on it and seal the end up. You can always cut the heat shrink off.

 

I used wider black tape and a small zip tie to make sure the tape doesn't let loose. 5 years and it's still sealed up.