What is this socket, why could it be unplugged?

[bright]

So checking the oil this morning, looked down and saw this

So had a bit of a hunt round and found this

Now I presume the cable from the second photo goes into the socket, but not sure as I didn't unplug it, and have only had the car a couple of months. one issue is the connecter on the cable is a bit battered. Is it one of those connections that could jam up if I push it in?

should I reconnect it? also what the fcuk is it for? lol

 

[markkram]

I suspect it was unplugged when the oil filter was changed.
Think it's the oil pressure sensor.
I'd plug it back in.

 

[Dr HMS Derv Destroyer]

Appears to be oil pressure sensor unit or maybe oil level sender.

Plug it back in, it's a release able connector so chances are you won't jam it

 

[rich-6]

Its your PAS pressure switch, They do sod all other than leak i've found!

plug it in and put a cabletie round it, I found mine had a tendancy to pop off because the clip wasnt up to much

 

[bright]

awssome, cheers for the help!