I have a 09 RA with 935xx kms and my exterior temp sensor is screwing with me. I start car and it reads outside temp ie 5C as I drive the temp rises over time ie 20 min it goes to 35C, actual temp still 5C. The driving was done on a hwy at constant speed 100km/h.

Has anyone had this issue? Or know how to fix it?

I have searched and there's a thread about one guy who had the issue and moved it but nothing about what caused it or how to fix it. He said the sensor is by the emblem on the front and the wire comes from the same bunch as the horn.

 

It seems the issue took car of itself after the car was parked and ran for 8 hrs straight (was driving 2200 kms and stopped to sleep). I think some water got in the sensor and evaporated after the car ran for a while.