New X5 - Low Tire pressure warning - cold weather?? anyone??

[marcx5]

i have a new x5, only a few days old... and i just went to get in my car and the tire pressure warning came on for one of the tires. it is about 15 degrees outside and i wonder if that can have anything to do with it?

rather than traveling, i've decided to stay where i am tonight and I will check it out again tomorrow. the tire looks fine, nothing noticeable (like a nail, etc.) and it does not 'appear' flat... but then again, these are run flat tires.

any suggestions? has this happened to anyone else?

can i just check the tire pressure with a guage to see the correct pressure and if it's normal... assume the sensor is broken??