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Incorrect/Slow external temp reading?

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Thebrits615

Member
Sep 1, 2022
84
19
Nashville, Tennessee
#1
Hey everyone,
Picked up my new 2023 M3 a few weeks ago. Something I am noticing is the external temperature reading seems off and inaccurate. I plan to do some more testing but something I have noticed is that it is extremely slow to update.

Yesterday it was about 26 degrees out but it read 55 degrees from the time I left my garage to my destination for about 15 minutes before slowly it started coming down 1 degree at a time over maybe another additional 10 minutes. Anyone have same observations?
 
#2
I think that many people have reported the same thing... all with heat pumps I believe. I don't have as much delay on my 2020 model 3 that doesn't have a heat pump. It does take a little bit of time before the temperature indicator ends up at the right temperature but it's not 15+ minutes.
 
#3
Thebrits615 said:
Hey everyone,
Picked up my new 2023 M3 a few weeks ago. Something I am noticing is the external temperature reading seems off and inaccurate. I plan to do some more testing but something I have noticed is that it is extremely slow to update.

Yesterday it was about 26 degrees out but it read 55 degrees from the time I left my garage to my destination for about 15 minutes before slowly it started coming down 1 degree at a time over maybe another additional 10 minutes. Anyone have same observations?
Click to expand...
yes and it has been that way for years. I would not say it is inaccurate. Just that it is slow to adjust to the actual temperature. My 2017 X takes about 10 minutes to adjust to a wide range. The 2020 version is about as slow. No big deal for me.
 
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#4
Silicon Desert said:
yes and it has been that way for years. I would not say it is inaccurate. Just that it is slow to adjust to the actual temperature. My 2017 X takes about 10 minutes to adjust to a wide range. The 2020 version is about as slow. No big deal for me.
Click to expand...
Thanks a bunch. Was just wanting to make sure this wasn’t a service visit on my new car. Good to know others have had similar issues. Thanks!
 
#5
Anybody also notice the internal temp inaccuracy? Feel like that one is worse than the external sensor. Vegas has been in 50F’s now and noticed parked in sun the “internal” temp reading will get up low 90s. But I know for sure going into car, it is cold and I need to put the heat on. Where are these sensors located? I feel this could impact the Cabin Overheat Protection and make it turn on when it doesnt need to or turn on more than it really needs to.
 
#6
Here is another thread on the same issue:
teslamotorsclub.com

Thermometer slow to adjust?

Is anyone else having a problem with their termometer registering the change in temperature within a reasonable amount of time? Just yesterday after pulling out of my garage (low 60's) and driving for several minutes 10-15, before the thermometer showed the correct exterior temperature of 35...
teslamotorsclub.com teslamotorsclub.com

It is a problem when you precondition the car inside a garage that is warmer than outside. It seems to lock in the garage temp for a long, long time after, which, for me, causes my windows to fog up because it thinks it is warmer out than it is.

I actually stopped preconditioning this year on a schedule to stop this from happening. If it is really cold (-20°C or colder) I usually turn on the car a few minutes before I am leaving instead.

If you don't precondition the thermometer is fine. I've submitted bug reports for this but nothing fixed yet sadly.
 
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#8
Im in the same boat here. Temp reading 10c ( garage temp ) for at least 15 mins. Actual ext around -20c.
First world problem i know.... But the HVAC uses the exterior temps as a reference. My heat is crap until the ext temp starts to read correctly.
This is an issue.
 
#9
kennykustom said:
Im in the same boat here. Temp reading 10c ( garage temp ) for at least 15 mins. Actual ext around -20c.
First world problem i know.... But the HVAC uses the exterior temps as a reference. My heat is crap until the ext temp starts to read correctly.
This is an issue.
Click to expand...
I have the same problem with my 2023 rwd. Even my 70 year old mother noticed the incorrect outside temperature when is around-20c outside. I sent in a service request and they said it’s normal. And they did an over the air diagnosis and my car was functioning properly.
It doesn’t happen all the time. But when it happens the windshield will fog up and turn on the defrost will make the temperature start to adjust with in a few minutes.
I think turning on the defrost o pens the vent to allow outside air to pass into the under hood area.
Lots of work arounds for the supposedly auto features.
 
#11
The Y is new to me.. I just traded in the Mach E.

I've always preconditioned with the Mustang due to the small heater in the Mustang in order to keep the batteries warm. I guess it's just habit that I'm preconditioning the Tesla.
Maybe I don't need to be preconditioning?
My commute is 45 minutes most of that being on the highway.
I'll try turning off departure for a few days and see what happens.
 
#13
I noticed this the other day as well, I just figured the exterior temp sensor was in the airflow path of the front heat exchanger.

If you were heating your interior that would make the outside heat exchanger cold, yes? So it would take a few miles of ambient air swirling around for it to get a correct reading.

If this is what’s happening not sure how you’d fix it other than relocating the temp sensor.
 
#14
Stew-2 said:
I noticed this the other day as well, I just figured the exterior temp sensor was in the airflow path of the front heat exchanger.

If you were heating your interior that would make the outside heat exchanger cold, yes? So it would take a few miles of ambient air swirling around for it to get a correct reading.

If this is what’s happening not sure how you’d fix it other than relocating the temp sensor.
Click to expand...
Mine usually takes about 15 mins of 120kph highway speed to level out. All the while the hvac is not working correctly due to it thinking its 10c, vs the -20c that it actually is.
 
#15
Again this morning. 15 mins at 120 kph. Still reading plus 10c. ( it was neg 25 outside ). Windows fogging up, and cold inside.
I did turn off pre conditioning.
Tesla service performed a remote hvac diag, and said everything was ok.
The ext sampling rate needs to be increased. How do i convince them of this ? Is there anyone at Tesla that you can actually speak to ?
 
#20
It’s not about the accuracy the temperature being displayed. It’s about the climate control not working properly due to the wrong temperature input.
The car will start to fog up after 5 minutes when the actual temperature is -20c. But the climate control thinks otherwise and doesn’t provide enough heating.
Dose anyone know where the temperature sensor is located?
 
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