Yesterday, Mon Jan15, went to go out mid morning for groceries, did the remote for warm up. Got in and checked the pressures, all 4 blank/dashes, Outside temp reading was 4 degrees. Did the drive, about 5 miles, temp was then 12 degrees outside, TPM sensors, all 4, began showing normal. Don't know if they got warm enough from the higher 12 degrees or if tires warmed up as they normally do from flexing and building their own heat. Evidently there might be a temperature operating range.

 

Sometimes older batteries in the sensor can cause this problem. I wouldn’t worry about it at this temperature

 

At 4F the tire pressure would be very low. Assuming it was 32 psi at 72F it would fall to around 20 psi a 4F. Which is too low for the sensor to measure.
Every 10 degrees means about 1 psi difference.

 

This is very basic physics. For a given volume of gas, the pressure is varies with temperature.

The softer the tires, the more the rubber flexes and the more heat they make as they roll.

It was around 0 F in my neighborhood yesterday morning and there were cars lined up at every tire sales place to get air added. Of course, they were mostly newer cars. Those without working sensors fail to notice.

 

I didn't start this thread to discuss tire pressure vs temperature, I started it to show/discuss effect of low temperature on the operation/function of the sensors.

 

I'm assuming the sensors/batteries are original OEM with the vehicle. 2011 1LT.
Once temps reach 10-12 degrees, function returns to normal.

If one or two sensors did that I could blame the batteries of the inoperable sensors, but all four at the same time and all 4 become operable at the same time.

 

Bought the HHR used in June 2023, one of the first things I did was check tire pressure vs indicated position. Easy to verify by letting some air out and checking display for verification. Sensors matched to position on car.
Tire pressures are all fine when ambient reaches 10-12 degrees.

I'm not seeking why, just reporting what I found.

 

The winter weather won’t last long, the cold is taking the batteries down, they should be fine with a little warm up.

 

OK.
I’ll delete my posts since you aren’t asking for help.

 

No reason to delete posts, I appreciate all replies.