This humble little icon just celebrated its 10th anniversary as a mandatory component on most passenger cars. But even though it could one day save your life, chances are, you may not know what it means.
It's your car's Tire Pressure Monitoring System (TPMS) warning light, which pops on when a tire's pressure falls below 25% of the vehicle manufacturer's specifications. The National Highway Traffic Safety Commission deemed it essential new-car equipment in 2008, in response to mounting evidence that tire failure is to blame for some of the nation's worst multivehicle, multi-fatality crashes. Low tire pressure usually precedes a blowout, when a tire flexes beyond its elastic limits, overheats, and the rubber separates from its internal fabric and steel cord reinforcement.
If you see the warning light, according to Bridgestone Tire, here's what to do:
Light comes on and stays on while you're driving
It means at least one of your tires is low. As soon as it's safe, pull over and check tire pressures with a gauge. Add air as needed. Then, see your tire professional to figure out why it's losing air. You could have picked up a nail, or your stem might have a bad valve.
Light goes on and off
Fluctuating temperatures affect the pressure in your tires (cold decreases pressure, heat increases pressure). One or more of your tires is likely borderline low, causing the light to come on when the tire is cold. Check with a tire gauge to find out which one.
Light flashes at startup and stays on
There's likely a malfunction in your TPMS sensors, and you need to get them checked by your mechanic.
Remember: By the time the warning light comes on, your tire's already in trouble – dangerously low and perhaps even damaged to the point it needs replacing. Experts recommend you check your tires every month with a tire gauge to catch pressure problems early. Check them when they're cold, not right after driving. That's especially important this time of year when cold weather causes tire pressure to drop.
They also say to reduce your chances of a blowout:
Don't overload your vehicle.
Get slow air leaks repaired immediately.
Replace any tire that has visible cuts, bubbles in the sidewall, or worn tread.