[Crash]

Hey guys, before I googled myself to death, I figured I would ask here. Noticed on my new CTD that the outside temperature is always showing 10-20 degrees higher than the actual temp.

Any thoughts?

Thanks

 

[obermd]

I'd take that in and show the dealership. I can see a couple of degrees since asphalt gets hotter than the surroundings.

 

[smkn600ctd]

Mine usually starts off high...then will drop down. But it's still higher than it actually is. I just contribute it to engine heat effecting the reading

 

[Eddy Cruze]

Mine is very accurate until its really hot out here. Although I don't have a Diesel I've seen 123 degrees F twice now!

 

[Tomko]

Mine is very accurate. I compare it to a NIST certified weather station I own.

Highest I ever saw was 43c.

The people blabbing on the radio and TV are often the ones who are wrong.

 

[ChevyGuy]

I'm not sure how it's calibrating itself, but I think a poor connection shows as a lower temperature. So a wiring problem to show a high would have to be some kind of restive short across the connector.

It might be a good idea to know where the senor is located - it's in the left fog light cover. Which is going to catch a lot of heat coming off the asphalt or solar heating since it's in black plastic. It's possible the sensor has slipped out of it's "home" and lying inside the bumper instead sensing the airflow.

 

[KpaxFAQ]

Mine is extremely accurate once you've been moving 5 minutes or so

 

[diesel]

Mine is very high when in stop and go traffic, but accurate once on the go.

 

[CruzeDan]

There's a bulletin involving the temp sensor. I'll try to get it up here sometime

 

[Cruzator]

Mine is fairly accurate below 70F. When it is in the 90's, I've seen it more than 10 degrees high if I am driving into the sunshine (with the sun hitting the front of the car). In the winter, it seems like it's right on. The sun load definitely effects it, as have been mentioned on the forum by many people.

 

[PanJet]

I have the same problem. Mine is nearly always a good 5-8 degrees high even after moving for a while. It's the least accurate OAT I've ever seen in any car.

 

[Tomko]

Against what other temperature source are you comparing it against?

 

[PanJet]

Against what other temperature source are you comparing it against?

Anything and everything: Official readings, banks or other pubicly visible readings while driving, other cars, other thermometers close by. It's almost always higher. In the winter it's not so bad.

 

[Tomko]

All those sources you cite are notoriously inaccurate. Those public signs, like at banks, are the worst.

My suggestion is that your car is more accurate than you think. It can easily be validated by the use of an infrared thermometer.

 

[Crash]

Concerning reference, I would say multiple sources. I think it is pretty obvious when the car says it is 91 out and it is only in the low 70's. I would notice/complain if it was 5 off, but 10-20 degrees is usually obvious.

Will have to look at mine in more detail, but I think it is always incorrect. And I almost never have stop&go traffic.

 

[Tomko]

Okay - 10-20 degrees off is genuinely raising a flag. Please keep us informed.

 

[PanJet]

All those sources you cite are notoriously inaccurate. Those public signs, like at banks, are the worst.

My suggestion is that your car is more accurate than you think. It can easily be validated by the use of an infrared thermometer.

I get that bank signs might be inaccurate, but when the official high for the day was 90 degrees where I live and my car was saying 98 or even 100 degrees even after driving for a while and this happens all the time, I know it's off.

I've owned four different cars, all with OAT gauges, and none of them have been as consistently high as this one.

 

[Tomko]

This official high numbers quoted by broadcasters are sourced from the thermometer of record, which is always an extremely accurate thermometer it is also located in a very specific, static location.

Typically it is at an airport between taxiways. Where the official reading is taken once an hour.

Driving around in the city will always generate higher temperatures than those official sources. It will also report temperature fluctuations that occur within that hour.

Weather is one of my other hobbies. I have pretty much the gold standard sensor suite for weather information collection installed on my lot.

There is an app from Davis Weather that will let you see individual readings in your area. This is something that will give you way more accurate information than any broadcaster will.

The app is called Davis WeatherLink Moble.

 

[dougc905]

Mine is always about 2°C high. This from observing ice on the car & road while the car says it is 2°C outside. Whatever. The thermometer is a toy and its placement on the car leads to inherent error.

 

[Tomko]

Air temperature can be above freezing and ice can still be present because that ice, by definition, is still frozen.

Air can change temperature quite easily and quickly. Other substances, especially those with mass (and water has a lot of mass) change temperature much more slowly.

Ever try to boil water with a hair dryer or freeze it with an air conditioner?

The temperature sensor is a lot more accurate than you think. Given its placement it is not giving you ground temperature, nor temperature of the vehicles hood. It is giving you air temperature at about one foot above ground.