The first cold morning of the season, a lot of Fort Lee drivers start the car and see a new amber light on the dash: a horseshoe shape with an exclamation point in the middle. That's the tire pressure warning light. Sometimes it's just the weather. Sometimes it's a nail in your tread. Here's how to tell the difference, how to check your tires yourself, and when to have someone take a look.
What the tire pressure light means
The light is part of your car's tire pressure monitoring system, usually shortened to TPMS. Federal rules have required this system on new passenger vehicles sold in the U.S. since the 2008 model year, so most cars on the road in Bergen County have one. According to the National Highway Traffic Safety Administration (NHTSA), the warning comes on when one or more tires is significantly underinflated, generally about 25 percent below the recommended pressure.
That's a meaningful drop. By the time the light is on, the tire is low enough to affect braking, handling and tire wear, so it's worth checking the same day rather than waiting.
- Solid light: At least one tire is low. Check the pressure and add air.
- Light flashes for about a minute when you start the car, then stays on: On most vehicles this means the monitoring system itself has a problem, such as a sensor with a dead battery or a sensor that wasn't set up after a tire change. Your tires might be fine, but the system can't warn you if they aren't.
Your owner's manual explains exactly how your car's system behaves, so it's worth a quick look.
Why it shows up when the weather turns cold
Air contracts as it cools. A commonly used rule of thumb is that tire pressure drops about 1 PSI for every 10 degrees Fahrenheit the temperature falls. If your tires were filled on a warm September afternoon and it's now a near-freezing November morning, they can easily be several PSI lower without any leak at all.
That's why the light often comes on first thing in the morning and sometimes goes off after a few miles, once driving warms the tires up. A light that turns itself off isn't a reason to ignore it. It's a sign the tires are sitting right at the edge and need air.
Tires also lose a little air naturally over time, even with no damage. Between the seasonal temperature drop and normal seepage, fall and early winter are when a lot of North Jersey drivers find their tires running low.
How to check your tire pressure
You only need an inexpensive tire gauge, and the whole job takes a few minutes.
- Find the right number. The recommended pressure for your car is on a sticker inside the driver's door jamb (sometimes in the glove box or fuel door) and in the owner's manual. Don't use the number molded into the tire sidewall. That's the maximum pressure the tire can hold, not the right pressure for your car.
- Check when the tires are cold. The most accurate reading is before you drive, or after the car has been parked for a few hours. Readings taken right after a drive will look higher than they really are.
- Check all four tires. Remove the valve cap, press the gauge firmly onto the valve stem and read the number. If your car has a spare that's meant to be used, check it too.
- Add air to the recommended level. Many gas stations have air machines. Add a little at a time and re-check so you don't overfill. Put the valve caps back on.
After you've filled the tires, the light should go off on its own after some driving. Some vehicles need a reset button or a menu setting; your owner's manual will tell you if yours does. NHTSA recommends checking tire pressure at least once a month, and in a Bergen County winter that's a good habit to keep.
When it's more than the weather
If you add air and the same tire is low again in a day or two, you probably have a slow leak. Common causes include:
- A nail, screw or other debris in the tread
- Damage from a pothole, which can bend a wheel or break the seal between the tire and rim
- A leaking or corroded valve stem, which road salt can make worse
- A cut or bulge in the sidewall
Take a look at the tire. A bulge or bubble on the sidewall is a safety concern, because it means the inner structure of the tire is damaged. In that case, don't keep driving on it at highway speeds; put the spare on or have the car looked at.
If the light came on suddenly while you were driving, the car pulls to one side, or you hear a flapping or thumping noise, pull over somewhere safe and check. A tire that loses air fast can overheat and fail.
Why correct pressure matters for North Jersey driving
Underinflated tires flex more, build up heat and wear unevenly, especially on the outer edges. They also take longer to stop and respond more slowly when you steer, which matters on wet or icy roads, in stop-and-go traffic near the George Washington Bridge, and on Route 4, Route 46 and the Palisades Interstate Parkway. Low tires also hurt fuel economy, since the engine has to work harder to roll them.
Keeping tires at the right pressure is one of the simplest things you can do to make the car safer through the winter. For the rest of your cold-weather checklist, see our guide to getting your car ready for a Bergen County winter.
When to have it checked
It's a good idea to have a shop look at the car if:
- The light stays on after you've filled all the tires to the right pressure
- The light flashes at startup, pointing to a sensor or system fault
- One tire keeps losing air
- You see damage, a bulge, or a nail in the tire
- The light came on after new tires or a tire rotation and won't reset
If any of these sound familiar, use Book Service to pick a time, or call us at (201) 224-8444 and tell us what you're seeing.
This article is general information for drivers. Your owner's manual and the tire placard on your vehicle are the best guides for your specific car.