Steady or flashing changes what you do
- A steady light means one or more tires are significantly low. Stop when it's safe and check all four with a gauge.
- Fill to the pressures on the sticker in the driver's door jamb, not the number printed on the tire.
- A light that flashes for about a minute and then stays on means the system itself has a fault. Check your tires anyway and get it serviced.
- Tire looks flat or badly low? Don't drive on it. Call roadside assistance.
First, look at how the light behaves. A steady light is about air pressure, so pull over when it's safe and check your tires. A light that flashes for about a minute and then stays on is different, because the monitoring system itself has a fault (cars with a separate TPMS light show faults on that light instead).
Either way, we'd grab a tire gauge before doing anything else. Tires that look fine still need a gauge check, and the light only comes on once a tire is significantly underinflated.
Check all four tires with a gauge
Your car's recommended pressures are on the tire information sticker in the driver's door jamb (inside the fuel filler flap on some cars) and in the owner's manual. Front and rear can differ. Skip the number on the tire's sidewall, which is the most that tire can take, not what to fill it to.
If your tires are a different size from the ones on the sticker, find out the right pressure for those tires before you adjust anything.
- Check each tire with a gauge, cold if you can, before you drive or after the car has sat for at least 3 hours.
- Compare every reading with its number on the sticker.
- Add air to any tire that's below its number, then check it again.
If the light came on while you were driving, check right away. A tire that's below its number even when warm needs air, but never let air out of a warm tire, because its pressure drops as it cools. Check again once the tires are cold.
If your car shows each tire's pressure on the dash, use a gauge anyway. Ford tells Bronco Sport owners not to use that display as a tire pressure gauge.
Some Chevrolets have Tire Fill Alert (opens in a new tab) to help. Park somewhere safe and level, shift to Park, set the parking brake and turn the ignition to Accessory or On with the tire pressure light lit, then add air until the horn chirps once. If the turn signal nearest the tire doesn't start flashing within 15 seconds, use a gauge instead.
After that, make a cold-tire gauge check a monthly habit, spare included, because the light won't warn you until a tire is significantly low.
What turns the light on
Work through these, starting with the ones you can check yourself.
Tires lose some air naturally over time, and cold weather drops the pressure further. Tires filled on a warm day can be low on a cold morning. The light may go off once the tires warm up from driving, but they still need air.
A nail or screw in the tread can let air out slowly over days or weeks, so look over each tire for anything stuck in it and listen for a hiss. Air can also escape at the valve or where the tire meets the rim. If one tire keeps needing air, have a tire shop find the leak.
Recent tire work matters too. A temporary spare can bring the light on, and replacement tires or wheels can keep the system from working properly. On a 2024 Ford Bronco Sport, the warning shows solid or flashing while the temporary spare is on, and the system works normally again once the repaired wheel and tire go back on.
On cars with pressure sensors in the wheels, a sensor with a dead battery, or one damaged when tires were fitted, sets off the warning too. Replacing a sensor takes a tire machine, a wheel balancer and a TPMS programming tool, so leave that to a tire shop or dealer.
After adding air, check whether your car needs a reset
Tire pressure monitoring comes in two kinds (opens in a new tab). A direct system has a sensor in each wheel that reads the actual pressure. An indirect system has no wheel sensors and spots a low tire by comparing wheel speeds through the anti-lock brakes, so it can't read pressure while the car is standing still.
What happens after you add air depends on the car, so we'd look up your own model's instructions before pressing any reset button. Chevrolet's tire pressure steps (opens in a new tab) are to set all the tires to the recommended pressure and drive, and the light goes off. A 2024 Ford Bronco Sport may need at least two minutes of driving over 20 mph (32 km/h) before the light goes off once the tires are inflated. A 2023 Honda CR-V needs a calibration every time you adjust even one tire's pressure.
If you drive a 2023 Honda CR-V EX-L
The CR-V doesn't measure tire pressure directly. Its system compares the rolling radius and rotation of each wheel and tire while you drive, and it doesn't monitor at low speed, so your gauge readings are what tell you whether the tires are right.
Honda requires a TPMS calibration every time you adjust the pressure in one or more tires, rotate the tires, or replace a tire. Before you start, set the cold pressure in all four tires, then make sure the car is completely stopped, in P, with the power mode ON. You can't calibrate with a compact spare fitted, and tire chains have to come off first.
On the EX-L's 9-inch touchscreen, Honda's calibration steps (opens in a new tab) go like this:
- With the power mode ON, press the Home button.
- Select Vehicle Settings, then TPMS Calibration.
- Select Calibrate, or Cancel to back out. If “Calibration Failed To Start.” appears, select Calibrate again.
Selecting Calibrate only starts the process. It finishes on its own after about 30 minutes of total driving at 31 to 62 mph (50 to 100 km/h).
Until then, the light may come on briefly if the power mode is ON and the car hasn't moved within 45 seconds. That's normal. It isn't the malfunction warning, which flashes for about a minute and then stays on.
On the CR-V, low temperatures and altitude changes can drop the pressure enough to set off the light, but overinflation won't turn it on. A compact spare, a heavier and uneven load than when you calibrated (towing a trailer, for example) or tire chains can also turn it on.
Sudden acceleration, slowing or steering, snowy or slippery roads, and tire chains can delay the warning or keep it from coming on at all. Mixed tire sizes or types can stop the system working properly, so stick with the same size and type. Honda recommends replacing tires with the same brand, model and size as the originals.
If the light comes on with properly inflated, specified regular tires fitted, skip another calibration and have a Honda dealer check the car.
When to get the system checked
A light that flashes for about a minute at start-up and then stays on will do that at every start until the fault is fixed, and it may not warn you about a low tire in the meantime. Keep checking with a gauge and have the car checked as soon as possible. Look out for that warning after any tire or wheel replacement, too.
If the light stays on after you've set every tire to the right pressure and followed your car's reset steps, or one tire keeps losing air, have a dealer or tire shop take a look.
Bring your gauge readings and the numbers from the sticker, what the light did (steady, or flashing then steady), any dashboard message, the weather when it came on, and any recent inflation, rotation, tire or wheel replacement, spare use or calibration attempts.
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