Technical Replacing Ambient Temp Sensor

[SqueekyCBJ]

Today, my wife experienced her first issue with our used 2016 500x. Upon starting the vehicle, she was receiving service engine and drive mode unavailable.

After searching these forums, it was also observed the outside temp was not being read at all. Showing -F

Stopped at a local auto parts store and confirmed the only error present was the Ambient Temp Sensor. Read the threads and know it's the nipple on the passenger side mirror.

My issue is I can't located an guides and white papers on replacing it. Would anyone here be able to provide some input. We are third owner so no dealer warranty and not looking to spend huge amount at dealership if it's something easily done at home.

Thank you in advance!

 

[Interstellarspike]

I recently had this happen too. 2016 500X POP.
Unfortunately the passenger side mirror needs to be replaced as the sensor is mounted to it. I was lucky enough that I had it done at the dealer under warranty. Apparently this is a common problem. Just as an aside, get your battery checked too as mine went bad shortly after & I think it may be related to the issue.

 

[s130]

Sensor is an integral part of the passenger wing mirror.

As your 500X is a 2016 model then you will still be in the 3 year warranty period. If not then you can a good case to still claim a good will repair from Fiat as this is a known fault/failure on all early 500X models.

 

[Stjrp]

I’ve got the same problem. Did you have a go? Would love to know if possible as a diy job. Thanks

 

[s130]

I’ve got the same problem. Did you have a go? Would love to know if possible as a diy job. Thanks

Mine was replaced under warranty.

I can tell you that the door card has to be removed because the cable connectors are secured inside the door itself. Also one or move trim/door card buttons will most probably break so you should get some of these as well.

When the dealer did mine the technician was open/honest enough to say that a couple of the buttons broke on removing the door card and I would have to come back again after the replacements arrived to have them fitted.

 

[luytom01]

NOTE: I’m no motor electrician and all repair work carried out was done at my own risk. If you were to carry out a similar repair, you do so at your own risk.

Symptoms: Engine Check Light lit, Start / Stop Unavailable, External Temperature readings extreme (88+ Degrees).
OBD 2 reader states fault code: P0072 - Ambient Air Temperature Sensor Circuit Low.

Recently (December 2025) replaced my faulty Fiat 500x Ambient Temp sensor on the passenger wing mirror without removing the faulty sensor in location.
I simply removed the door mirror colour cover, traced the 2 wires leading from the faulty ambient temperature sensor and cut the wires (making sure I disconnected the car battery first) to fit the new replacement sensor by soldering the 2 wires.
As for the sensor head itself, I simply found a location away from any obstructions, especially the motorised mirror, and super glued the sensor in place.
It now works perfectly and no engine check lights or any faults showing.
Note: the new Fiat 500x Ambient Temp sensor was purchased via well known ‘rain forest’ website. Works perfectly.

 

[DGPunto]

It's quite easy to go one step further by removing the mirror glass (carefully) and fitting the replacement sensor in the original place. Had to do that on mine last year. In my case the sensor came from the well known auction site