When the temperature drops, you may notice a warning light near your vehicle’s gauges. If the warning light looks like a deflating tire surrounding an exclamation point, don’t freak out; it’s an easy fix.
This warning light happens because tires, of course, are filled with air. That air responds to the environment, and gets warmer or colder with the seasons. In late fall and winter, the air is colder, so it is also denser, which means less outward pressure in your tires than earlier in the year, leading to a warning light.
Some vehicles will tell you which tire is low. If you are not sure, you can use a tire pressure gauge ($1 at hardware stores and gas stations, $10 for fancy ones). Simply unscrew the valve stem cap from the tire, and attach the nozzle end of the gauge. You should hear it hiss, and the meter will pop out the back end displaying the current pressure. For this article, let’s say it showed “20 psi.” PSI is pounds per square inch, which is science-speak for how much air pressure is necessary to keep your 5,000 pound SUV from riding its fancy rims on the asphalt.
There are two places to look for your recommended tire pressure. The first location is in the driver’s door jam. Open the door and look for a white sticker with small writing. In addition to other useful information about your vehicle, this sticker shows the optimum pressure for your factory tires. Now, if you traded out your 18 inch wheels for some chrome 20 inchers, you have changed the tires and the pressure requirement. In this case, look on the sidewall of the tire. You should see a maximum pressure, let’s say 50 psi. Do not exceed that. In most brands, you will also see a recommended pressure, something like 36 psi.
Now, drive to the nearest gas station that offers free air, as you should not be charged for something that is free and abundant. Turn on the air machine, and attach the hose to the valve stem the same way you attached the gauge. You will hear it hiss. Give it a few seconds, and check your tire pressure again. It should have gone up. This will give you an idea of how long you will need to use the inflator to get your tire at the proper pressure. The bigger the tire, the longer it will take to inflate.
Finally, go for a drive and see if the light goes out. If so, your problem is solved. If not, the tire pressure monitoring sensor might be faulty, and you should have a mechanic look at it. If you want to permanently avoid the seasonal pressure change, consider having a dealership or tire shop fill your tires with nitrogen, a stable gas that is less responsive to temperature changes.