CEL on...temp gauge all the way on red...digital engine temp -128C

[Dado 540]

Driving enjoying the 540i and the "check engine" light comes on. 10 minutes after i notice the temperature gauge is all the way to the right on the "red".

I pull over immediately and check the digital engine temperature read out and it says -128C (yes negative 128)

No sign of any coolant issues. No smoke. Nada.

After fiddling around and just letting it cool off, turned the car on a few times but the needle rockets to the red zone. I figure its gotta be a malfunction with the some sensor, i started her up and drove off. Check engine light remained on, however the temperature gauge went back to slightly below the half way mark while i was driving. Engine temperature digital output was 70C and increasing slowly making its way to 85. By that time i was home and the needle was on the center.

Gonna inspect the coolant level once its cool enough, even tho i did not get "low coolant level" message. Definitely gonna have to get her scanned.

Anyone with ideas of a possible culprit(s)?