TPMS (tire pressure monitoring) triggers at about 25% below the recommended cold pressure. A cold-weather pressure drop, a slow leak, or a tire that's actually flat all light the same indicator.
First, look at the tires before driving. A visibly flat tire is a flat tire — don't drive on it. If all four look normal, check pressures cold. Top up to spec at the next gas station with a working air pump.
If you have a flat or a slow-leak puncture, we run tire service at $249 / hour, 1-hour min. Plug-and-patch is included when the damage is in the tread. Sidewall damage = flatbed to a shop.