It means that one or more of your tires has low air pressure. The dashboard warning light, which looks like a cross-section of a tire with some lines in it, comes on when the tire pressure is 20% below what the vehicle manufacturer recommends. So, if your recommendation is for 35 psi (pounds per square inch), the light will come on when your pressure falls to 28 psi.
It’s important to note that 20% below recommended pressure is significantly under-inflated. This means that you will be experiencing degraded handling and that your tire will be running hotter than it should. This can not only be a safety hazard, but your tires will wear prematurely and could even suffer a heat related failure.
You should not use your Tire Pressure Monitoring System (TPMS) warning light as your trigger for checking your tire pressure. You should still check tire pressure at least once a month.
Some people mistake the tire pressure printed on the side of the tire as the recommended pressure for the vehicle. This is not the case. The information on the tire is the range the tire can handle. The correct pressure for your vehicle is on a plate or sticker on the driver’s side door or door jamb. This is the pressure your tires should have to match the engineered handling capacity of your vehicle. Please note that the pressure may be different for your front and rear tires.
You TPMS does not have a regularly scheduled maintenance interval. However, be aware that the batteries in the sensors mounted in each wheel will eventually die, illuminating the warning light and necessitating replacing the sensor. Sensors can also be damaged by road salt and other contaminants.
Some TPMS systems indicate tire pressures for individual wheels which will tell you which tire is low – as long as the system has been reset after rotating your tires. Other systems will simply give a warning and it is up to you to check all your tires (including the spare).
The government mandated TPMS systems to reduce tire-related accidents, property damage, injuries and deaths. Please have your tire pressure checked at least once a month to maintain your safety and increase tire life.