There is a delay built into the temperature sensor so that the temp doesn't "bounce" up and down quickly. Air has to come across the sensor as the car moves so if the sun is shining on the car while standing still, it will raise the temp and may take several minutes to adjust to the outside air. I park my car in the garage and it takes several minutes to come to the correct outside temp especially when there is a big difference between the two. The temp is controlled digitally, unlike the temp you see on an outside thermometer.

 

I noticed the same thing on my 2017 Sportage SX. There's a bit of a delay for the outside air temp sensor to read the correct temp. This is a bit annoying since it messes with the auto-climate control. I have to drive a bit for it to read the right temp before I enable it. On my old Acura CSX it always had the correct outside temp the moment I turned on the car.

 

The temp reading is probably correct. It probably is programmed to change slowly to avoid jumping from temp to temp, because its a dynamic situation as you drive down the road.

 

My wife’s 2020 EX Tech is garaged so the car is warmer than the outside winter temps. It usually takes about two miles of driving in colder temps before the 39 degree warning announces itself. My 2019 RDX is similar. Takes a short drive for the the system to account for the new cooler outside temps.

 

Upon starting my Kia (2020 Sportage) the ambient temperature reading seems to display whatever it was when I last turned it off. It then slowly transitions to the current temperature over a period of 5 minutes? Can anyone explain why/how it could work this way?

How would a thermistor “remember” what the temperature was the last time the car was turned off?

 

This is a digital thermometer whose output is managed by your car's computer which has a flash memory. The computer slows down the registering of the reading so that the temperature doesn't jump all over the place as you drive.

 

I understand what you are saying but why on earth would they have it smoothed over such a long period? Granted you don’t want it jumping up and down with a meaningless level of precision. But why start at a temperature when you turn the car on that is 20 degrees below the current ambient temperature and take 10 minutes to get to current ambient? I deal with sensors in my job every day that utilize smoothing like you are talking about to keep from whipsawing control systems and screwing up a process. I can think of no reason to program the ambient temperature sensor in a car to behave the way this one does. If its used for auto-climate control (my car doesn’t have that feature) it would mean my AC would not be working right by the time I finished my commute.


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From my experience, the programmed rate of change of the outside temp seems to be a constant. That means it will take significantly longer to reach the final temp when the difference is larger. From your experience, it seems that the rate of change is probably 2 degrees per minute. The only way the outside temp affects the auto climate control is use of the defroster. There is another thermostat inside the car for the climate control. It might be nice to know the outside temp right away, but I don't see how it will affect any other system in the car. You might suggest to Kia that they change the rate of change when differences are large. The way it works now is fine with me, however.

 

Don’t get me wrong, its not really creating a big problem for me. As much curiosity as anything else. I guess I don’t buy that its intentional by design. I can think of no useful reason for it to remember what the temperature was nine hours earlier when I shut-off the car. We have 20 degree swings here from morning to afternoon so its very noticeably wrong. It is used for the ice warning so if you were to park your car when its 40F and then get back in it in the evening when its 25F the warning is not going to function right. Honestly I can’t think of why you would put any smoothing on it. If was to keep the defroster from turning on and off that could be done in the control for the defroster while still allowing for the freeze alert to function correctly. Either way there is no reason to use the temperature when the car was last turned off as a starting point.


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You seriously can't tell the difference between 40 degrees and 25 degrees just by stepping outside. Or, possibly by looking at windows (no frost = above freezing, frost = below freezing). This whole post seems like a lot of noise over something extremely trivial. Reminds me of the children's book "When You Give a Mouse a Cookie". The more "extras" manufacturers put on a car, the more they open themselves to trivial complaints.

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I can come up with scenarios where it would make sense to use the last outside temperature. For example, you park in a garage where the temp is 30 degrees warmer than the outside. My guess is that the programming for the thermometer is not that sophisticated that it can vary the rate of change given the differential in temps. In today's world, probably the best starting point would be the internet outside temp for your location -- but our cars do not have a non-tethered internet connection. The logic could use AI, but that is far too sophisticated for a less important function like this. Basically, however, I agree with you that it could be more sophisticated. My guess is that it is more sophisticated in luxury cars that have functions like seat memory. Remember, we have a "mundane" compact SUV at a reasonable price point. For extra dollars, I'm sure they could do a lot more.... Before they change this, I'd like those memory seats (which has been available in other cars for a couple of decades....)

 

I guess. Can’t see why it would cost anything to program it correctly. There is absolutely no valid reason for it not to drive both the interior readout and freeze indicator either directly, or with a time true threshold of 1 minute or less.

I get if its a cheap thermistor that takes a long time for the resistance to respond to temperature changes, although I’ve never seen one this slow. My cheapo meat thermometer is quicker. But that still doesn’t explain the lag on start up of the car. Still can’t believe its intentional design. I need a better argument for that if its going to satisfy my curiosity.

You can have whatever features you want instead. I don’t care if they fix it or not. I just want a logical explanation of how it works.

Thanks!


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Corporate decisions on features vs. cost via sales is an interesting discussion. If you add all of the features in a lower level vehicle, like the Sportage, then you devalue those features in higher priced cars. Increased features may also be increased cost in memory, programming, and parts. It's a corporate dance in how to maximize sales and profits. You try to come up with a balance. Obviously, competition is also involved in that discussion. You try to find the cheapest thing you can find to make the car slightly better than competition. Marketing, finance, production, and engineering are all involved in those discussions. I've been a part of those discussions over the years and each function has input. Generally, consumers want all of the features and generally believe that the cost is slight, so why not just add them. Well, if you could get everything in a luxury car in a compact SUV, then the value of the luxury car is decreased and so are profits and margins. You can get a luxury compact SUV from Porsche, Audi, and Lexus (and soon from Genesis), and I'm sure the programming will be much more sophisticated (and I could get my memory seats). Personally, I'm looking forward to the Genesis 70 series SUV coming out in 2021. I'll probably move to that in 2022.

 

Right but....I’ve never seen instant read ambient thermometer in a sales brochure for a Lexus.

Just thinking about it some more, I don’t think it always starts out at the temperature it was at when it was last turned off. Time for some more observations and investigation!


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The Lexus has a lot of little features that are not in the sales brochure but are expected in a luxury vehicle. It's only highlighted in the sales brochure if the competition doesn't have it. But if you don't have the expected luxury, people who lay out that money will complain and it will be an issue.

 

70 Series?
Way out of the 'price range' of most folks who purchase Kia......

 

The 80 series SUV starts at $50K so I expect the 70 series to start at $40K or so. The base model of the 70 will probably have all of the features of the SX which is about $32K. So I'm not so sure it is "way out of the price range".....

 

So it sounds like there may be something defective with mine based on other comments. That makes a lot more sense to me than the idea that it’s designed to work that way on purpose.

 

Mine doesn't take 10 minutes but it does take two or three minutes to stabilize at the correct temperature which I would figure is normal.

 

Its not just the time it takes to adjust, its that its 25 degrees off when I start the car. Ambient temperature would be 50 and the readout shows 25, which is what it was when I parked jn the morning. After 10 minutes or so of driving it finally gets to 50.

It may be a design trait that people would never notice if you don’t live somewhere with such big temperature swings. I was just trying to understand why it would be designed that way or how it could fail that way. Curiosity mostly.

Thanks for your observations.


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Sounds like a trip to the dealer as something is wrong with your temperature gauge.

 

I have the same problem. The outside temperature reading on my 2020 Sportage has been off by as much as thirty degrees when I start it. It takes a long time adjusting until it gets to what might be, or might be close to but who knows, an accurate reading. By the time it is possibly correct I am at work. I’ve gotten nowhere with this issue with the dealership and with Kia consumer services. My two previous Kia’s, both Optimas, did not have this problem. The temperature reading was accurate from the start.


USA
2020 Kia Sportage EX

BTW, I just got home and parked the car. The outside temperature is reading 115 degrees Fahrenheit but the true outside temperature is 84 degrees Fahrenheit. Why have this if it isn’t even close to accurate???

I've never thought the temperature would be the same as it was when the vehicle was shut off., but other vehicles I've owned are within one or two degrees of the actual temperature when starting the vehicle. I have a 2010 GMC Acadia and if it is -5 outside, the reading in the car is -5 when the car is started. There is no slowing moving from +5 down to -5. My Sportage 2015 also read the temperature accurately, no movement up and down.

My two previous Optimas gave accurate outside temperature from the start. No good reason why my new Sportage is off by as much as thirty degrees when I start it and takes the whole ride to work to become accurate.

 

I have the same problem. The outside temperature reading on my 2020 Sportage has been off by as much as thirty degrees when I start it. It takes a long time adjusting until it gets to what might be, or might be close to but who knows, an accurate reading. By the time it is possibly correct I am at work. I’ve gotten nowhere with this issue with the dealership and with Kia consumer services. My two previous Kia’s, both Optimas, did not have this problem. The temperature reading was accurate from the start.


USA
2020 Kia Sportage EX

BTW, I just got home and parked the car. The outside temperature is reading 115 degrees Fahrenheit but the true outside temperature is 84 degrees Fahrenheit. Why have this if it isn’t even close to accurate???


My two previous Optimas gave accurate outside temperature from the start. No good reason why my new Sportage is off by as much as thirty degrees when I start it and takes the whole ride to work to become accurate.

Sensor is in cabin?

 

Higher than ambient temp readings are normal here until you start driving. I dont know where the readings are taken but it is a Kia specific problem.

To be fair, I don't park under shade during the day and I live in Phoenix, AZ so we will routinely be above 110° in summer and will approach 120° often enough.

2007 Nissan Sentra (white paint color several years ago).

2020 Kia Sportage S (these days it was already hot 100+°)

 

This part week:

Within a few minutes it had cooled down to 115° or so to ambient and I live 4 miles from this location. It dropped a degree every few seconds sitting in the parking lot where I was as soon as I started the engine.