Your car's tire pressure monitoring system or TPMS is there to warn you when the air pressure in your tires is low, and it will turn on if one or more of your tires is underinflated. Seeing the TPMS light on your dashboard turn on and stay on is cause for alarm, you might not know what it means when the light starts flashing. Let's take a look at what that means and what you should do if it starts happening to your vehicle.