Tire pressure sensors are super flaky. Mine come on randomly all the time, and after the first few dozen times I stopped to put a real gauge on them and saw that all four were right at the rated pressure, I've gotten to the point where I just ignore it and punch the button on the dash to hide the warning. It's the kind of false negative feedback that is especially unhelpful.

It doesn't help that it is completely opaque what the thresholds are for when the warning light goes off; I also don't know whether one is supposed to recalibrate anything if you change the type of tire that you are running - for instance, I run snow tires during the winter that have a different PSI rating than my all-seasons the rest of the year...