Tire Pressure indicators-how accurate?

[gobluefan]

With all this cold weather in the Midwest (-7 degrees F this morning, -2 degrees yesterday), I got a first-time dashboard warning yesterday about low tire pressure.

From the time I first got the car in September, the 4 tires have all been consistently at 31 psi. Yesterday, they were all at 25 or 26 psi after sitting outside in the cold. The tire pressures increased to 28 psi after driving on the expressway for about 10 minutes.

Here is the part I don't understand: Three of the 4 tire graphics on the dashboard had flashing numbers (indicating low pressure), yet the pressures for all 4 wheels were the same! Do you think the tire pressure indicator system for one wheel (rear passenger side) is defective?

I did fill the tires with more air last night, and the low pressure warnings went away after a few minutes of driving.

My car is the 2015 Genesis 3.8L V6 Ultimate with AWD.

 

[ksoze]

Just a thought - if the one tire was even a little more inflated when it was reset, then it may not have reached the warning trigger point as early as the other three tires. Winter plays havoc on tires pressure and is a non-stop battles of warnings with todays systems...

 

[gobluefan]

Thanks for an explanation. Can you tell me how to reset the tire pressure warning setpoint?

 

[Midnightsun]

This is preset,no adjustment.

 

[JimB47]

FWIW I have an Accutire digital guage I use to set pressure. On my Genesis, the monitoring system in the car reads 1 pound higher than the Accutire guage. The guage has a resolution of +/- 0.5 psi while I assume the car monitoring system has a resolution of +/- 1 psi since it doesn't display pressure in less than 1 psi increments. So I have found the overall system to be very accurate.

The rule of thumb for pressure loss due to cold weather is 1 psi per every 10 degrees F.