So as I'm pulling out of my street with the wife and kids to head to the park I hear a "dong." I look down to see the tire pressure warning.

So I pull over and take a look at the detail screen which shows the rear driver's tire at 25psi. When I got out to look it looked fine - the same as all the other tires. At first I thought maybe it was a sensor malfunction, but then I noticed a nice little nail in the tread.

Luckily, the nearby Mr. Tire was able to patch it - with no wait and for $18.

So anyway, the sensor works.