I leased a new 2012 Suburban LTZ two weeks ago, and I'm encountering the same odd issue that drove us a little nuts with our 2009 Suburban:

It seems to happen primarily on early spring or late fall days when the temperature is at or near freezing overnight, but mild during the day. (In the most recent incident, the local temperature was around 60, but the outside temperature gauge stayed stubbornly stuck at 37 degrees). The incorrect temperature reading in and of itself isn't particularly bothersome, but it's making it impossible to keep the A/C on. (It just turns itself off from the false reading).

We've never been able to get over to the dealership in time to duplicate the problem, and their diagnostic equipment is not generating any codes.

We had the same elusive issue with the 09, but really hoped the problem would have been resolved with our 2012 replacement. We love our Suburban, but this problem is a little maddening.

Any thoughts?

 

Welcome to the forum.

Mine did that one time. Several months later when having the oil changed, I had them check it and they replaced the temperature sensor.

 

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I agree with 73shark, you may need to have the temperature sensor replaced. Is there anything blocking the sensor (behind the front grill)?

Louis
GM Customer Service

 

No, nothing I'm aware of. The Suburban has not been modified or accessorized in any way.

Thanks for the feedback guys, but the dealer is resistant about replacing a part when they can't duplicate the problem.

 

You need to explain to your dealer that it's the service after the sale that keeps people coming back.

 

also:
any type of aftermarket grille insert or anything that alters airflow into the rad will skew the temp sensor reading. If this is the case you may have to relocate the sensor.

the ambient temp sensor will update depending on certain criteria. Untill the conditions are met; it will read the last/old reading.

 

Thanks, but there's nothing aftermarket attached to the grill or anywhere else on the vehicle?

Could frost or condensation be a factor?

 

I will search for the enable criteria for the temp sensor update. You can then perform this procedure and verify the accuracy of the sensor.

 

Thanks!

 

the sensor displays current temp readings:

-at engine start up after more than 2.5hours after the engine was shut off

-ect temp is less than ambient air temp at start up

-sensor reading at start up is less than last stored reading