What is this plug?

I just got done changing my timing belt, waterpump and thermostat.  Got it all back togeather, flushed the remaining coolant and added new stuff. Got all the air bubbles out and topped it off.  Coolant temperature is normal but the oil temp caught my eye.  It showed 350+ degrees.  I know it was not that warm because it had only been running for a few mintues.  I looked under the hood and I found this plug but I cant find the other end.  I must have forgoten to plug it back in.  there are two wires brown with white stripe and white with green stripe. Here are some pics.  Thanks in advance.

Oh come on...someone has to know.  I have to get my car on the road.

all the plugs in the car are unique and fit only one way. all you have to do is locate the male connector for that plug..

there are several tempreature sensors in the B5 A4 throughout the coolant system, so it's not that far fetched to guess that might be one of them.

it looks like the coolant expansion tank sensor, did you plug that one back in.

I have a feeling its for my oil temp sensor.  My oil temp says 350+ degrees as soon as I turn my key.  I can not find the male end of the connecter  thats why I am asking.