Wildly inaccurate temperature display

[Agentlongwood]

I live in Orlando Fl, and today was a very nice 74 degrees Fahrenheit.  When I got in my car I noticed the readout on the home screen said it was -40F... I got a laugh at first but then I noticed that since the car thought it was arctic outside, it would not run the AC, no matter what temp it was set to or even on "Max AC."  After driving for about 10 minutes and sweating the temp readout started climbing.  Over 5 minutes or so it got up to 72, and normal A/C function resumed.  It's still a bit inaccurate, by the time I parked it was saying it was 68 out when it was 72.  This is not the first time it has done something like this, but it is the most ridiculous.  I'm guessing a sensor somewhere has gone bad, but I truly don't know.  Any ideas on how to check or fix it?  Car is a 2014 MKS Ecoboost with 62k miles.

 

[ZSHO]

I think your MKS should have an Ambient Temp Sensor located behind the grille.  Z
http://www.rockauto.com/en/moreinfo.php?pk=2603322&cc=1503823&jsn=548&jsn=548

 

[Agentlongwood]

It's only $9... Can't beat that lol.  I'll look around and see if I can find where it's located on the car first.  Just to make sure there's nothing obviously interfering with it.

 

[SHOdded]

Should be right there behind the front bumper cover on the pass side.  So will need to remove bumper cover first.  DIY 4 sure.

 

[sholxgt]

I have had this exact same thing a few times.  Had the dealer update all of the body control modules to the latest flash available and it seems to have helped.  Now when it's off it doesn't last long and isn't off by as much.  Not enough to keep the A/C from working.  Service manager said he sees it often and that, in his experience, when it's an intermittent problem changing the sensor does not help.  Said it's software related.  Mine works well enough now with the modules updated.