So I have had a code lately. Found a melted one way valve above the air filter. Replaced it. Got another code. So my car almost never reaches the middle in the gauge for engine temp. Last night it was barely registering anything then it slowly climbed. My temperature for the outside has been all over the place. Sometimes its dead on. It's been 90 degrees in the day lately and 70's at night. Last night it told me it was -2 degrees Farenheit. Then jumped to 30 degrees then back around again moving every few seconds. Do I need to replace both or just one?? How hard is it to replace and how much is the part? I have automotive knowledge but this Audi is different..

 

check your outside temp sensor. im not sure where its located cuz i own a vw jetta but i had the same problem with it reading crazy temps. mine is located in front of the driver side wheel under my bumper. mine was hanging below the bumper, so it was exposed to all elements. i went & hid it up in the bumper & problem was solved.

 

This could be where mine is at. My mom ripped off my front spoiler the other day on a curb so there is a good chance mine is located there and was exposed..