External Temperature Reading Inaccurate

[Terran]

After completing my charge at work, I went to move my RAV so others can utilize the charging station. It’s 95+ degrees today and my exterior temperate reading is 64 degrees. I drove the car for about 30 min and now read 72 degrees. Is this common or do I have a bad temperature sensor?

 

[mark_rivers19]

After completing my charge at work, I went to move my RAV so others can utilize the charging station. It’s 95+ degrees today and my exterior temperate reading is 64 degrees. I drove the car for about 30 min and now read 72 degrees. Is this common or do I have a bad temperature sensor?

my outside temp is consistent with the day's forecast +/- 2 degrees.
if coming from a covered garage, it will show a cooler temperature, but it will quickly rise up in less than 5 minutes of highway driving

 

[DevinL]

If the behavior continues, I'd say you've got a bad temperature sensor. My RAV was parked next to my college weather station yesterday and read 100°F at about 4PM. The weather station was reporting a little over 98°F. Whenever I've compared the RAV to the weather station output, the results have been ±2° which is pretty accurate all things considered.

 

[Terran]

If the temperature sensor is bad, would this affect how it regulates the battery cooling/heating?

 

[DevinL]

If the temperature sensor is bad, would this affect how it regulates the battery cooling/heating?

Good question, but I would imagine that it doesn't. The TMS would use temperature sensors within the battery pack itself rather than ambient temperature data.

This is how it works in the LEAF - although there is no TMS on that car but there are multiple temperature sensors in the battery pack that help the charging and CHAdeMO system determine things like rate of charge.

 

[Takinamulligan]

I noticed the exact same thing as the original poster last week (before I noticed this post). 90 plus outside and the vehicle was indicating it was around 65. It slowly worked back up and seems to be okay now.

 

[dipper]

I noticed the exact same thing as the original poster last week (before I noticed this post). 90 plus outside and the vehicle was indicating it was around 65. It slowly worked back up and seems to be okay now.

For any Toyota, this is normal. When you power up the car, it is reading your last temp before power down.

Like you said, the reading will be okay after a little bit when it settles down.

 

[Bassman]

Mine did exactly the same. The dealer replaced the outside temp sensor. It still does it once in awhile. Who knows why. It takes 45 minutes to an hour of driving before it reads properly.

 

[dipper]

Mine did exactly the same. The dealer replaced the outside temp sensor. It still does it once in awhile. Who knows why. It takes 45 minutes to an hour of driving before it reads properly.

I have never seen this in 4 (different models and years) Toyota in my household. Everyone changes within a few minutes close to the outside temp.

 

[EVBill]

After completing my charge at work, I went to move my RAV so others can utilize the charging station. It’s 95+ degrees today and my exterior temperate reading is 64 degrees. I drove the car for about 30 min and now read 72 degrees. Is this common or do I have a bad temperature sensor?

I had the same problem when using a Chargepoint station near work. In the morning I would plug it in and the car accurately displayed the outside temperature, low 60's. When I went to pick it up at lunch time the outside temperature would be anywhere from mid-70's to high 80's and the car was still displaying whatever the outside temperature was when I plugged it in. If I drove it around a while it would take a very long time to slowly go up.

Here's what disturbed me the most though: Last year I installed a temperature sensor in the coolant hose for the DC-DC converter. Whenever I charged at home with my 40A EVSE the radiator fan always came on when the coolant reached 135 degrees F. When using the Chargepoint station at work there were times I would pick up the car and it was still charging. On some hot days (mid-80s, low 90s at lunch time) the coolant temperature gauge would be up to 150 degrees F and no sign of the radiator fan turning on. I estimated the Chargepoint station to be around 22-25A vs my 40A at home, and thought there might be an issue in the software related to charging rate and temperature. I discussed this with the dealer and they didn't have a clue. The dealer suggest I call the Toyota 1-800 number. I stopped using the Chargepoint station at work and just charged at home, I never bothered to call the 800 number. However, if others are having this issue as well maybe I'll give them a call.

I never experienced this problem using my 40A EVSE at home, the car displays the correct temperature and the radiator fan always comes on when the coolant temperature reaches 135 degrees F. As a side note, whenever I start the car after it sat in the parking lot at work all day the coolant temperature gauge has always been within a couple degrees of the car display for external temperature. And in the morning the two temperature readings are always exactly the same when I start the car. Only when using the Chargepoint station at the 22-25A rate did I see inaccurate readings with the car temperature display.