Unused Plug?

[NoQuarter]

Under the intake and throttle body on my X5 is a plug that seems to never have been used. It has no protective cap on it.

You can't see it in this pic but this is where it is located

Anyone recognize this plug/location? I could not find the male side of the plug anywhere.

 

[doublespaces]

Is that one of the knock sensors? Pretty sure they sit on cylinder 2 and 5 area.

 

[NoQuarter]

Is that one of the knock sensors? Pretty sure they sit on cylinder 2 and 5 area.

Good thought. I'll look into that