Ambient temperature intermittent

[GTP]

A couple of times my ambient temperature reading has been off. First was on a cold day, then on a hot day.

Throws off the auto climate control, obviously. Sooner than later, it corrects itself.

Anyone else?

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[FordTechOne]

A couple of times my ambient temperature reading has been off. First was on a cold day, then on a hot day.

Throws off the auto climate control, obviously. Sooner than later, it corrects itself.

Anyone else?

That's the normal operation of the AAT display. The ambient temperature reading is filtered, meaning it doesn't display what the temperature sensor is actually reading until the HVAC module strategy has determined that it's a valid reading.

The purpose of filtering the input is to prevent readings being induced by heatsoak. Once the vehicle is driven above a predetermined speed for a predetermined amount of time in order to get airflow across the sensor, it will display an accurate ambient air temperature reading. That is the reason you may see non-updated readings at low speeds, after a cold soak, or in traffic.

 

[GTP]

Thanks for this info, but I'm sorry if I am having a hard time fully accepting it.

Example 1 - cold day
Temp reading was 55F (IIRC) when it should have been about 30F. Did not read properly all day. Worked normally again the next day.

Example 2 - hot day and after autocrossing (though my car had been parked for an hour before I got in it to leave)
Temp reading was 55F when it was actually 81F outside. To get the AC going, I had to switch off AUTO mode, and set things manually. The ambient temp corrected itself within a few miles on the road.

So, I would say Example 2 is consistent with your info, but Example 1 is not.

IOW, I am not convinced if I have an intermittent problem, or if it is working as designed. :shrug:

 

[FordTechOne]

Thanks for this info, but I'm sorry if I am having a hard time fully accepting it.

Example 1 - cold day
Temp reading was 55F (IIRC) when it should have been about 30F. Did not read properly all day. Worked normally again the next day.

Under what conditions did you operate the vehicle? If you parked it when it was 55 degrees, it will read 55 degrees when you start it up again. As I said, the vehicle needs to be driven at a specific speed (55+MPH, generally) for a specific amount of time (approximately 10-20 minutes) in order to allow the reading to update. If you only drove around town or at low speeds, the reading would have remained the same.

 

[jeffrt]

Kicking up an old thread... My temp readout has started doing the same thing. It's mid 80's out today, and my readout sat at 73 for quite a while. Finally updated itself after driving for 10 mins or so, but even then it was working it's way slowly up to the correct temperature. Seems odd to me. My Focus ST never did that.

 

[MSMStannyl]

I noticed something like this for the first time a few days ago. It's definitely not something I was looking out for. I've had my car for 1.5 years and never looked at the temperature and thought something was off...until the other day. As far as I could tell, this was the first time the temp reading appeared to be showing incorrectly for an extended period of time.

I thought it was a little odd but didn't pay enough attention to it to remember exactly what the readings were but I believe it was showing a significantly cooler temperature than it could've been outside. Eventually, I looked down at it again and it was correct.

This issue sounds like it can be explained by FordTechOne's post. However, I will say that I have never noticed anything like that before or since. Granted, I don't always check the temps (although I will now).

What's interesting is that I had no idea that the exterior temp display had anything to do with the HVAC "Auto" setting. I just assumed that was a readout to give you an "FYI" about the temp outside. I assumed there were other sensors inside the car that would work with the "Auto" HVAC setting.

 

[jeffrt]

Well, at least that's a few of us with the same thing happening to confirm what FordTechOne said. Only seems to act up when it's really hot out. Haven't had to bring the car to the shop since I've had it, so looks like I can still hold out.

 

[RIBS]

Mine has done this also....way off for a period of time...then suddenly corrects itself..or not.

 

[MakStang]

Reviving an old thread... Same here. 2017 EU spec Mustang EcoBoost. Today the temperature reading stuck at 28 C (82 F). It's a really hot day (95 F). I never had this issue before. Yesterday I had to re-flash the tune using COBB Accessport and I guess this somehow resets the whole system (sort of like unplugging the battery). Could this be the reason? This doesn't seem to have affected the operation of the A/C.

I guess I will wait for a couple of days to see if it corrects itself like [MENTION=19918]FordTechOne[/MENTION] said and, if not, I will take it to the dealer.

By the way, does anyone know where the ambient temperature sensor is located, or at least post a link that will help me locate it? I would like to unplug it to see if this will have an effect.

 

[jasonstang]

Reviving an old thread... Same here. 2017 EU spec Mustang EcoBoost. Today the temperature reading stuck at 28 C (82 F). It's a really hot day (95 F). I never had this issue before. Yesterday I had to re-flash the tune using COBB Accessport and I guess this somehow resets the whole system (sort of like unplugging the battery). Could this be the reason? This doesn't seem to have affected the operation of the A/C.

I guess I will wait for a couple of days to see if it corrects itself like [MENTION=19918]FordTechOne[/MENTION] said and, if not, I will take it to the dealer.

By the way, does anyone know where the ambient temperature sensor is located, or at least post a link that will help me locate it? I would like to unplug it to see if this will have an effect.

It's in the front bumper behind the lower grille on the passenger side.

 

[MakStang]

Thanks [MENTION=19308]jasonstang[/MENTION]. I will try to disconnect/reconnect it tomorrow. I hope it is easily accessible.

 

[MakStang]

That's the normal operation of the AAT display. The ambient temperature reading is filtered, meaning it doesn't display what the temperature sensor is actually reading until the HVAC module strategy has determined that it's a valid reading.

The purpose of filtering the input is to prevent readings being induced by heatsoak. Once the vehicle is driven above a predetermined speed for a predetermined amount of time in order to get airflow across the sensor, it will display an accurate ambient air temperature reading. That is the reason you may see non-updated readings at low speeds, after a cold soak, or in traffic.

UPDATE: I can confirm FordTechOne's post above. After driving the car for a few minutes at +/- 50 mph, the temperature reading updated and it now works normally.

[MENTION=19918]FordTechOne[/MENTION] thanks for the info and for explaining the reason behind this glitch.

 

[articrandom]

I brought my car in for a potential issue with the A/C and got told during the first call that the A/C won't kick in if ambient temperature sensor is below 50F? I said, fine then have it sit at the dealer for awhile until the sensor warms up.
In the second call they told me this:
So they had the car sit in the dealer for awhile and saw that the temperature sensor had not change so they decided to replace it and they still saw that it was not reading fine so they finally told (or figured out) me what you guys have been mentioning here, that it won't give an accurate reading until the car has been driven at above a certain speed for a few minutes.

Is what they are telling me really accurate? Is this normal or can we make the ambient temp sensor operate as most of the cars out there and not be speed and time constrained?

 

[MakStang]

Don’t worry, it works as on any other car. The above posts describe what to do if the temperature reading on the dash stops working.

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