My 2012 reads the external temperature off by a consistient 2 degrees whether its 100 out or 40 out. So the slope appears to be correct. Is there a place you can adjust the reading? Do I have to get the dealer to replace the sensor I have? Anyone else have good readings so I know changing the sensor might actually resolve the issue?

As a reference I drive by three signs back and forth to work. My 2004 F150 and 2012 Acura match all three to the degree so I know its the Mustang that's off.

 

Could be where the sensor is located on the Mustang and other factors... Why is 2 degrees a big deal?

 

What instrument are you using to compare to your car thermometer?

 

To answer the first question; 2 degress is 2 degrees when my other two vehicles are zero degrees. I can see 1 degree as every digital instrument can be +/- a digit. If it is an easy fix I'd like to do it. Is your temperature reading right, or is it off as well?

And if it was sensor placement I would expect it to have a different slope or change its readings based on the car (hot engine, cold engine, AC on, etc.) but it seems to stay the 2 degrees all the time. So I think wherever Ford put the sensor is in a good location.

To answer the second question three signs with the temperature and my other two vehicles. I would be hard pressed to understand how five readings were all off, and all off exactly the same. But I would lik eto know if others have seen their temperature readings off. Maybe its similar to the complaints people have raised that the car's computer always calculates a lower mpg than if you do it manually.

 

Digital electronics are still based on small incremental variations, plus there are tolerances in sensor accuracies. 2* at 100* is 2%. That's fairly small. 2* at 40 is 5%, and that's getting large.

If you are measuring coolant temp, it will vary, considerably, depending on where you read it. And as mentioned, how are you comparing your readings?

If you are talking ambient outside temp, dont bother; that's not measured but is inferred and calculated.

 

Its the location of the AAT sensor.
You find a place on the vehicle where
the sensor would not be influenced by
the heat the vehicle is producing.
The Challenger's AAT is located on
the front grill opening for the radiator.
The most uninfluenced place while the
vehicle is in motion but that changes
when you stop motion and air flow.
I have yet to find the AAT sensor on
my S197 be it on the wiring diagrams
or the actual sensor on the vehicle.
It always seems to be off any amount
it wants to be at any given time.