Temperature reading

[JimboSlice]

I live in Arizona (I know “Why?”), I have posted about my temperature reading on the screen reaching 145 degrees. This is the second summer it has reached this milestone. I just got McQueen back from the dealer which they have changed the temp sensor along with a couple other issues (speaker rattle and cracked door pillars). The temp still goes up to 136 degrees and the temp fluctuates up and down and my fan still sounds like a V8 engine. My question is what does that temp reading measure? External temp or battery temp?

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[AliRafiee]

External temperature

 

[rreddy3]

I had been wondering about the accuracy of the ambient air temperature display. Mine typically reads 2 to 4 degrees more than a weather app. It made me wonder if the display was adjustable as it was on some ICE vehicles I've owned.

Turns out there is an old, long thread on the temperature display.

Outside Air Temperature Discrepancy | MachEforum - Ford Mustang Mach-E News, Owners, Discussions, Community

I didn't read the whole thing but the gist of it seems to be the sensor is effectively reading the reflected pavement temp at a height equal to the bottom of the bumper cover above the shutters on the driver's side. That reading is distributed by the car to various modules. Scanning through some of that thread, I get the impression that is more important to the car and its management systems than weather report/app temps. Weather report/app temperature is said to be measured differently which gives a lower reading that's more representative of what we feel outside. For me the punch line is I'm not going to worry about the temp displayed in the car if it's in the same general neighborhood as the app temp displayed on the phone.

 

[macchiaz-o]

I'm surprised your dealer replaced the sensor.

Yeah, higher than expected readings are normal here, as we've seen in numerous past threads.

I've put a probe thermometer in the car if I'm curious about cabin temp, and use Google, Alexa, or the car's connected navigation if I'm curious about nearby outdoor temps.

 

[DugthePug Dad]

If you have PPF, check if they put it over the sensor

 

[RickMachE]

I'm surprised your dealer replaced the sensor.

Yeah, higher than expected readings are normal here, as we've seen in numerous past threads.

I've put a probe thermometer in the car if I'm curious about cabin temp, and use Google, Alexa, or the car's connected navigation if I'm curious about nearby outdoor temps.

Dealer didn't know what they were doing I expect.

 

[MBCook]

Mine is about 10° high in summer and I think I’ve seen it 10° low in winter. It’s just not useful.

 

[rreddy3]

I'm surprised your dealer replaced the sensor.

Yeah, higher than expected readings are normal here, as we've seen in numerous past threads.

I've put a probe thermometer in the car if I'm curious about cabin temp, and use Google, Alexa, or the car's connected navigation if I'm curious about nearby outdoor temps.

I think I’ll just take my Thermapen with me in the car …. or not… ?

 

[macchiaz-o]

I think I’ll just take my Thermapen with me in the car …. or not… ?

I'd worry about it's electronics or battery going bad, plus that's insanely expensive! But hey people wrap their cars and buy service contracts so everyone's got their thrills, right?

This $8 analog thermometer's been working great for its purpose (satisfying my curiosity):

Taylor Instant Read Analog Meat Food Grill BBQ Cooking Kitchen Thermometer with Red Pocket Sleeve for Calibration, 1 inch dial, Stainless Steel https://a.co/d/hhoWJjG

 

[MW1515]

https://weather.com/science/weather-explainers/news/car-thermometer-thermistor-temperature-wrong

 

[Mach-Lee]

Check that the temp sensor isn't covered if you have front PPF. Almost all installers cover it by accident.

Higher readings after being parked or stopped are normal because the sensor doesn't have any airflow. Ford has a bulletin out on this. You have to drive 25+ MPH for a few minutes before it will read the air temperature accurately.

Since the sensor is near the ground, it will read higher than weather stations during periods of intense sun and little wind.

 

[rreddy3]

I'd worry about it's electronics or battery going bad, plus that's insanely expensive! But hey people wrap their cars and buy service contracts so everyone's got their thrills, right?

This $8 analog thermometer's been working great for its purpose (satisfying my curiosity):

Taylor Instant Read Analog Meat Food Grill BBQ Cooking Kitchen Thermometer with Red Pocket Sleeve for Calibration, 1 inch dial, Stainless Steel https://a.co/d/hhoWJjG

I wouldn’t actually take the thermapen in the car. Just joking. It was a birthday present a few years ago.

 

[JimboSlice]

I don’t care what the temp is outside. I can handle if it’s reading 10 degrees higher but not 30 degrees and making my cooling fan work over time which sounds so loud. No I do not have protective film on my car.

 

[macchiaz-o]

I don’t care what the temp is outside. I can handle if it’s reading 10 degrees higher but not 30 degrees and making my cooling fan work over time which sounds so loud. No I do not have protective film on my car.

The battery and powertrain electronics have their own temperature sensors. I would imagine the car's cooling fan and compressor are loud because they're above thresholds that call for more cooling, or because the cabin occupants want more cooling.

Maybe one of the folks that monitors their cars with OBD-II scanners and the like can chime in to let us know if they've confirmed this or found otherwise.

 

[Mach-Lee]

I don’t care what the temp is outside. I can handle if it’s reading 10 degrees higher but not 30 degrees and making my cooling fan work over time which sounds so loud. No I do not have protective film on my car.

It’s working normally. Cooling fan and compressor are going to ramp up hard to cool the battery and cabin if you are parked in 100°F+ temps. Everything has its own temp sensors, that’s not the only one. Remember to leave it plugged in as much as you can to keep things cool, and use remote start for 10 minutes before you get to the car so things have a chance to cool down first.

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