Outside temperature sensor calibrate?

That's ambient air Temp. Aka, not direct sunlight. Park your truck in the shade and I bet it's less than a degree off.

 

Yep, you can get a good idea by looking at multiple stations near you: https://www.wunderground.com/wundermap

 

haha yeah, based on what the forum is telling me I think I'll call my local meteorologist and tell them to use Tacoma temp for tonight's newscast.

 

Right, but it's still pretty specific to the spot the sensor is at. For example: your link shows 82°F and 86° F where I'm at, but my phone's apps both say it is 79°F. Also, your truck has to factor in wind speed for an accurate reading, which isn't always consistent. If your truck is sitting or in stop and go as you stated, the onboard reading will likely be much higher when you're in the hot sun. It works vise versa for the winter as well.

 

THIS. I think you nailed it, thanks.

 

Supposedly only 115 outside.

 

Just some friendly information since we are on the topic:

The faster the sensor is moving through the air, the more accurate it's reading. Inanimate objects do not feel a 'wind chill' factor like humans do, so they don't read low if they are traveling at highway speeds. They are actually more precise this way.

This is because more air particles collide with the sensor, giving it more information about what the temperature is. And temperature is just a convenient term to describe the energy of a fluid. To a temperature sensor, the air has no more or less energy than it actually has, regardless of speed (up until very very high speeds that a Tacoma cannot travel at). It just is what it is.

Others have accurately explained why a temp sensor will read high while parked or in stop and go traffic. The particles hitting the sensor from hot objects around it influence the air particles hitting it.

Temp sensors are simple and well understood devices. There is no need to calibrate them, unless you modify your truck in some way. But from the factory? Not at all.

 

To ensure accuracy weather apps receive their temperature from a transmitter mounted in a white slatted enclosure mounted several feet off the ground away from any structures to minimize errors created by heat radiation. All bets are off unless truck sensor is mounted in same box.

 

Sort-of. There are three means of heat transfer. Convection, conduction, and radiation.

As I said earlier, the ground absorbs heat on a sunny day and in turn radiates it right back into the air. (Why is the inner city always 2-5° hotter than the suburbs? Because concrete radiates more heat than green space.) Similarly, walking across a hot parking lot is not in your imagination, it really is hotter. Its more noticeable during the summer when walking across concrete is miserable, and asphalt is unbearable. That's not from the sun, that's from the ground.


So to read air tempreature, you need your sensor to read only air temperature, and isolate it from other sources of heat. Back to conduction, convection, and radiation. The temp sensor is relatively insulated from conduction already (except from air particles), but in order to get an accurate read on air, you need to isolate it from radiation. So again, the best way to isolate the sensor from radiation is to get airflow (convection) to the sensor. That way it is reading the air and not the ground.

 

My butt sensor is extremely accurate.

 

Inner city pressure?

https://www.youtube.com/watch?v=7wqfcwgT0Ds

 

Interesting trailerguy, my new '22 is exactly 4°F high as well. And this is not my first car, and I understand moving will regulate the heated metal temperature around the thermocouple, and I do know the actual temperature as my phone is sitting beside me, or I call my wife and ask what her car says, which amazingly matches the phone (but mine does not and is always - (winter or summer) 4°F off. It would be great (and I see this on forum after forum after forum) if the first x# of pages were not devoted to the questioning of the poster's question. I would love to know (also) if there is a way to calibrate the outside temperature thermocouple. That's all. Because even if I did not understand anything about why I am asking and the sensor is correct, that will also be made clear after calibration.

 

The outside temp. always seems to be close enough. It's the inside temp. that I am concerned with.

 

The short answer appears to be "no." But, as I mentioned earlier in the thread, your phone is based on wherever the local temperature sensor is for your particular location. However, many factors go into temperature readings. I also pointed out that temperature can vary as much as 5° in even my small town of 4.5 square miles. So calling your wife doesn't really mean anything unless you're driving next to one another and comparing directly.

But, as the saying goes: A man with a watch will always know the time. A man with two watches is never really sure.

 

FWIW, the FSM doesn't have a calibration procedure. There are specified resistance values at different temperatures. If out of spec, you replace it.

 

My '22 has always been high too. by probably about the same amount. And it's high in every situation whether in the sun, shade, parked on hot asphalt, in a garage, or in dirt. I'm glad you brought this up. I've been meaning to ask about this during my 10k service but probably would have forgotten. It is scheduled for a couple weeks out but I'll try to report back if the dealer has any meaningful feedback.

 

My ‘20 has also always read high. I was hoping someone would come up with a recalibration.

My 2003 F150, which I drove for seventeen years and 252,000 miles, always gave a spot-on temp, regardless of location or temp outside. This, of course, was in relation to external sources: phone app, bank temp/time sign, radio station, etc. It can be done.

 

As to the OP, I do the calibration in my head, and don't give it a second thought. As to the OP, it's already done to 4*. I don't see a problem, now can we move on to more pressing butt temperature?

 

Necessity is the mother of invention.

 

My dash temperature has always been off, like really really really low all the time compared to every other reputable temperature source. For example, just yesterday I KNOW for a fact it was 45 degrees outside, but my dash said it was 7 C. Oh yeah, the C thing, its always even given me an error message "C" for cold I guess, because its been broke ever since I bought the truck. Now that I think of it, my rate of speed has always been really off too, and its not because of aftermarket tires or anything. I'm stumped.