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Ambient Air Temperature Reading is Wrong!

Jack Christensen
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Jack Christensen Enthusiast

Jack Christensen

Posted
Posted

2019 Silverado Trail Boss LT Z71: 9,500 miles

 

My ambient air temperature reading on the infotainment system has always been about 7 - 10 degrees higher than what the actual temperature is.  I have taken it into the dealer 2 times. The first time, they "Said" they tested it and it looked normal.  I doubt they tested anything as it was just one of the items on a list of about 5 other things they were doing with my truck.  I took a pic of the temp on my phone/watch next to the infotainment temp and it showed an 8 degree difference.  They said to keep an eye out for updates to the system.. Ugh.  I took it in again about 2 weeks ago and a different dealer replaced the sensor.  Apparently it is in the passenger side mirror?  Anyway, that did not fix the issue.  It is still not accurate!

 

I read another post on a different site and it said to try an instant update by: 

To perform an instant update of the Ambient Temperature Sensor, simultaneously press and hold the Re-circulation button and A/C button on the HVAC control head.

 

I am going to try this over lunch - i'll update my post soon.  Anyone else have this issue?

Photo Sep 23, 7 36 04 AM.jpg

newdude Senior Enthusiast

newdude

Posted
Posted

They never are accurate.  Its in the pass. mirror.  The information to the temperature display is also "filtered" so there is some buffer or delay to its reading.  I wouldn't sweat an ounce more about it unless it starts reading -40F or 198F.  Then you know its a bad sensor. 

 

Quote

 

Outside Air Temperature

The Ambient Air Temperature Sensor is located in the Passenger Outside Rearview Mirror and varies it’s resistance with temperature. The Engine Control Module (ECM) reads the resistance value to determine temperature. The time of and rate of the temperature update is based on an algorithm in the Engine Control Module (ECM) software. Factors such as, last reading, current reading, length of time vehicle is been off/on, power mode, vehicle speed, driven distance, and sensor location are all considered by the Engine Control Module (ECM) to know when to update the displayed temperature on the Info Display Module. For example, if the sensor is located near the engine compartment, and the vehicle has been turned off for only 10 minutes then restarted, the ECM will wait until the vehicle is driven to get more accurate air flow across the sensor before it updates the display.

 

 

 

 

  • Like 1
amxguy1970 Senior Enthusiast

amxguy1970

Posted
Posted

It won't be very accurate, where readings from a phone come from either a official source and reading location locally (either through a local news center or national weather center readings) a vehicle uses a sensor at that point and can have so many things impact it. Heat from the black asphalt, shade, wind speed from driving, precipitation, etc. Use it as a ball park, and if you really want to test it take a thermometer and place it right by the sensor, that is more accurate what your truck is reading versus your phone at that point as apps vary depending on which is being used. Shoot, I just pulled up two different news sites locally, one shows 48 degrees and the other 53 degrees. Don't put much in to it.

 

Tyler

Jack Christensen Enthusiast

Jack Christensen

Posted
  • Author
Posted

Thanks for the feedback!  My 2004 Silverado was always accurate.  I guess I am too much of a perfectionist.  I expect things on a new truck to be accurate or work in general ; )  No biggie, more of an annoyance than anything else!  

econometrics Senior Enthusiast

econometrics

Posted
Posted

My 2007 Silverado temp readout was much more accurate than my 2019, too. 

 

I find that once you get going down the road, the truck reading gets closer to the weather station readings. It probably has to do with the airflow around the sensor. When it's just sitting there under the passenger mirror in the sun, it's likely perceiving the temp of the mirror dome. 

  • 1 year later...
Rare100thHD New Member

Rare100thHD

Posted
Posted

I just cut an air flow hole in the bottom of my mirror......therefore it cools down the heat built up inside the mirror sitting in the hot sun......corrects temp much faster now....

kelly mccue New Member

kelly mccue

Posted
Posted

I have a 2020 2500HD Chev truck with ambient air temp. off by 12-14 degrees. Its been in the chev shop 4 times. Seems to get worse every time that I bring it in. The temp. pod was replaced twice. The temperature reading is close when I start up the but as I drive the truck it gets worse, showing warmer , never consistent.

kelly mccue New Member

kelly mccue

Posted
Posted

I have a 2020 2500HD Chev truck with ambient air temp. off by 12-14 degrees. Its been in the chev shop 4 times. Seems to get worse every time that I bring it in. The temp. pod was replaced twice. The temperature reading is close when I start up the but as I drive the truck it gets worse, showing warmer , never consistent.

  • 10 months later...
Andret77 New Member

Andret77

Posted
Posted

Quick question. The temp has read -40 a few times today and then has really been all over the place. I know this is a symptom of a faulty ambient air temp sensor. However, my pass mirror adjustment is not working either. Do you think there could be a power issue? I have the new temp sensor coming in today. My AC has been intermittent for two months. truck was bought in September but the service times are so long I won't wait a week. 

redwngr Senior Enthusiast

redwngr

Posted
Posted
3 hours ago, Andret77 said:

Quick question. The temp has read -40 a few times today and then has really been all over the place. I know this is a symptom of a faulty ambient air temp sensor. However, my pass mirror adjustment is not working either. Do you think there could be a power issue? I have the new temp sensor coming in today. My AC has been intermittent for two months. truck was bought in September but the service times are so long I won't wait a week. 

What truck and engine?

Transient Senior Enthusiast

Transient

Posted
Posted

Remember, it's a thermistor, not a thermometer.  Car companies use them because they are cheaper.  The downside is they aren't as accurate.  I've been buying new GM vehicles for 16 years now.  All have/had the ambient temp readouts.  All are grossly wrong when I first driving the vehicle.  All get/got within +/-3°F after driving for about 2 minutes.  It's accurate enough.  That's what matters.

K455 Enthusiast

K455

Posted
Posted

My 19 Custom TB reads about 7degrees high since new,not worth it to me, to bring it in and have the dealer touch it and be worse or something else

  • 1 year later...
Robert Donohue New Member

Robert Donohue

Posted
Posted

I have a 2019 Chevy 3500 Duramax that always shows the engine light on when the ambient temp goes wacky. I have had it changed twice in three months by the dealer but the light comes back on within a few days. Can you tell me if there is another fix to try? I appreciate any further insight you can provide.

32BEAB42-1F4C-4B0A-BA10-B33767EFF032.jpeg

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