Hopefully that helps.
When I had this code come up, I replaced that sensor first. Didn't fix the code.
Then I had my timing belt service done because it includes the water pump, and I was due for the service anyway. Didn't fix the code.
Then I read somewhere that a missing belly pan could cause this because when outside temp is cold and there's no belly pan, then the cold air rushes into the engine bay throwing off the sensors. I had lost my belly pan the previous winter due to it cracking off from ice buildup. Got a new belly pan and installed it. Helped the temp guage a bit, but still the code came back.
Finally I decided to tackle the thermostat myself. Well sure enough it was stuck. New thermostat, car gets up to operating temp quickly and stays there. Haven't gotten the code since.
So, I would certainly start with the coolant temp sensor since it's cheap and relatively easy to replace. But if it doesn't fix it, you see what I had to go through. If you're not due for timing belt service I'd go right for the thermostat. About $100 and a couple hours of your time.