Just a quick suggestion, although I have no numbers in front of me for conversion...could it be it is reading Celcius and not Fahrenheit or vice versa?

 

Could very well be that, hit the left knob in your cluster and see what happens.

 

For Celsius the numbers would be much lower. But yeah -- checking for the right temp scale is essentially free so do that first.
Max temperature for the gauge is 122 degrees F / 50 degrees C.

Usually, the temp sensor goes bad by shorting out or a bad connection (open circuit). Open circuit = -40 degrees F and short circuit = 122 degrees F.

The sensor is mounted in a floor panel under the front left of the car. Run the car up on ramps, remove the sensor and clean the contacts on the sensor and the connector. If that doesn't work, replace the sensor.

 

Yeah first thing i checked. I also checked if it got knocked loose....... not that either. Probably just a bad sensor.

 

I am having this problem also (e46) it was raining hard yesterday and I accidentally fan over a curb on the driver side today the sensor I reading craziness, -40 +122, it beeps every time it goes to up or down. Maybe it's loose? Is there any way to check this without ramps?

 

You probably ripped the wires out. You'll have to get under there and look.

 

Thanks!

Beast dog btw!

Is that something I can do without the racks?

 

Yep. Should be able to just stick your head under there and see it.

 

My sensor has NEVER consistently read the correct temp. It is usually 10 to 20 degrees below, then sometimes it is right on. I have had 4 of these things over the last 3 years and I just got tired of it. BMW has replaced it a couple times under the parts warranty. This is the one thing about my BMW that irritates me because every other car I have ever been in with an outside temp sensor is always just a non-issue with the owner, always correct! Why are ours so problematic?

 

I took out the sensor on my ZHP by running over a piece of re-tread on the freeway and it set off the CEL. Happened while the car was under warranty and the dealer replaced it no charge. I think it was the only freebie that I got from BMW.