First and foremost, if your car is signaling to you that your tire pressure is low, you need to take it seriously and check it out. As of 2008, a law was put into effect for all newly manufactured vehicles to have a tire pressure monitoring system (TPMS). A TPMS gives a warning that the PSI of a tire is too low. Unfortunately,  this will not appear until the air pressure is at least 25 percent lower than what is recommended by the manufacturer.