A tire pressure warning light that stays on usually means at least one tire is low enough to need air, so check all four tires with a gauge and fill them to the pressure on your driver's door jamb sticker. If the light flashes for a minute or so when you start the car and then stays on, that typically points to a problem with the tire pressure monitoring system itself rather than the air in your tires. Hillside Auto Clinic at 26122 Western Ave, Lomita, CA 90717 can check both; call (310) 956-5794 or schedule.
What the tire pressure light is
The light is part of your car's tire pressure monitoring system, often called TPMS. It looks like a horseshoe-shaped tire cross-section with an exclamation point in the middle. Most cars built since the late 2000s have one. Its job is to warn you when a tire has lost enough air to affect handling, braking, tire wear, and fuel use, often before you'd notice it by looking.
Solid light vs. flashing light
- Solid light after you start driving: one or more tires is likely underinflated. Check pressures soon and add air.
- Flashing for about a minute, then solid: this usually means the system has a fault, such as a sensor with a dead battery, a damaged sensor, or a sensor the car can't read. Your tires may be fine, but the system can't warn you if one goes low, so it's worth having it checked.
- Light came on suddenly with a pull, noise, or a tire that looks flat: pull over somewhere safe and look before driving farther. A fast loss of air can mean a puncture or a damaged tire.
Why the light often comes on when it gets cooler
Air contracts as it cools, so tire pressure drops on chilly mornings. A tire that was borderline on a warm afternoon can dip low enough overnight to trigger the light, and then the light may go off once the tires warm up from driving. That's a sign the tire is close to the limit, not that the system is broken. Top it off to the door jamb pressure and the on-and-off light usually stops. Even in the South Bay, the cooler mornings of fall and winter are when a lot of drivers first see this light.
What to do when the light comes on
- Find a safe place to stop and take a quick look at all four tires for anything obviously flat, a nail, or damage.
- Check pressures with a gauge. Do it when the tires are cold if you can, meaning the car has sat for a few hours or been driven only a short distance.
- Fill to the pressure on the door jamb sticker or in your owner's manual. The number molded on the tire sidewall is the tire's maximum, not the right everyday pressure for your car.
- Drive a few miles. On many cars the light turns off on its own once pressures are correct. Some vehicles need a reset button or a menu step, which your owner's manual will explain.
- Watch whether it comes back. If one tire keeps losing air, it may have a slow leak from a nail, a bad valve stem, or a leak where the tire meets the wheel.
Common reasons the light won't go off
- A slow leak that keeps letting one tire drop.
- A worn-out sensor battery. Many TPMS sensors sit inside the wheel and run on a sealed battery that eventually wears out, so the sensor usually gets replaced as a unit.
- A damaged sensor or valve stem, sometimes from a pothole, curb hit, or a tire change.
- New wheels or tires without working sensors, or sensors that weren't set up for the car.
- A system that needs a relearn after tires are rotated or sensors are replaced. Some vehicles need a tool or a specific procedure so the car knows which sensor is at which corner.
- The spare. On some vehicles the spare has its own sensor, so a low spare can keep the light on.
Why it's worth not ignoring
Driving on underinflated tires makes them flex and heat up more than they should, which can wear them faster, hurt fuel economy, lengthen stopping distances, and in the worst case lead to tire failure. A light that's been on so long you've stopped noticing it also means you won't get a warning if a tire actually goes low.
Simple habits that help
- Check your tire pressures about once a month and before long trips, including the spare if your car has one.
- Keep a decent tire gauge in the glove box rather than relying only on gas station gauges.
- Look at your tires when you fill up, and mention any slow leak at your next service.
- If you rotate your tires, ask whether your car needs a TPMS relearn afterward.
Hillside Auto Clinic is open Monday–Friday 8 AM–6 PM and Saturday 10 AM–3 PM (closed Sunday). Visit us at 26122 Western Ave, Lomita, CA 90717, call (310) 956-5794, or email hillsideautoclinic@gmail.com.
Call or schedule
Tire pressure light that won't go off, or one that flashes when you start the car? Call (310) 956-5794 or book online. Mention your make and model, whether the light is solid or flashing, and whether one tire keeps losing air so the shop can plan the check.
FAQ
Is it safe to drive with the tire pressure light on?
For a short distance to get air, usually yes, as long as no tire looks flat and the car drives normally. Check and fill your tires as soon as you can. If a tire looks flat, the car pulls, or you hear flapping or thumping, stop and don't keep driving on it.
Why does my tire pressure light come on in the morning and go off later?
Cold air lowers tire pressure, so a tire that's slightly low can trigger the light on a cool morning and then read fine once driving warms it up. Filling the tires to the door jamb pressure usually fixes it.
What does a flashing tire pressure light mean?
A light that flashes for about a minute at startup and then stays on usually means the monitoring system has a fault, such as a sensor with a dead battery or one the car can't read. It's a good idea to have the system checked.
What tire pressure should I use?
Use the pressure on the sticker inside the driver's door jamb or in your owner's manual. Don't use the maximum pressure printed on the tire sidewall as your everyday setting.
Can you check my TPMS sensors?
Call (310) 956-5794 or use our schedule page to set up a time, and let the shop know what the light is doing.
