I had the same problem after changing the coolant...
...and dealing with a leaking drain plug (because I had 2 gaskets!!). I think Jeff is right. In my case it resolved itself in about a day, but I was getting ready to take apart the harness connector, and glad I didn't have to because I found it difficult to get my hands around, being where it is.

Originally Posted by
632 Regal
is this from a short or bad sensor?
Hate to take all the fun away from the turbo thread LMAO.
Thanks guys
1995 E34 540i Manual Limited Edition -- #50 out of 70 Australian RHD. Have owned 3 x E34 535i 5 speeds and E36 328i 5 speed (in the US), and a 1982 E28 528i, RHD Australian Euro-type 5 Speed.