Solid: one or more tires is at least 25% below the recommended cold pressure (FMVSS 138). Slow down, stop somewhere safe, and check all four tires with a gauge; inflate them to the pressure on the driver’s door jamb label (Honda). Flashing for about a minute, then solid: the monitoring system has a fault; have it checked (FMVSS 138, Honda, Ford).
What the tire pressure light means
US cars and light trucks built since September 1, 2007 must have a tire pressure monitoring system, after a phase-in from 2005. The federal standard, FMVSS 138, requires the low-pressure light to come on within 20 minutes once any tire is 25% below the vehicle maker’s recommended cold pressure, and to stay on as long as it is. The light must be yellow (FMVSS 101).
At 25% low, a tire is already well under-inflated. The owner’s manual statement the standard requires explains why it matters: an under-inflated tire overheats and can fail, and it also wears faster, wastes fuel and can affect handling and braking (FMVSS 138).
What to do when it comes on
- Ease off. Drive carefully and avoid sharp turns and hard braking (Honda).
- Stop somewhere safe and look at the tires for a flat or a puncture.
- Check every tire with a gauge, ideally cold: the U.S. Tire Manufacturers Association checks tires that have been parked at least three hours.
- Inflate to the label pressure. The recommended pressure is on a label on the driver’s door jamb or in the owner’s manual (USTMA, Honda).
- Drive a short distance. With the pressures right, the light should go off (some cars need a reset; see below). If it comes back, look for a slow leak and have the tire checked.
Why it comes on on cold mornings
Air pressure drops with temperature. Michelin puts it at about 1 psi for every 10 °F; the U.S. Tire Manufacturers Association says 1 to 2 pounds for every 10 degrees. A tire that was a little low on a mild day can cross the 25% line on the first cold morning, and the light may go out again as the tires warm up while you drive. That’s a sign to top them up, not to ignore it. Michelin checks more often in winter, because cold weather speeds up air loss.
Flashing, then solid: a system fault
When the monitoring system itself has a fault, the federal standard makes the light flash for 60 to 90 seconds each time you start the car, then stay on (FMVSS 138). Honda describes the same: about one minute of blinking, then steady. Honda lists two reasons: a problem with the system, or a compact spare tire on the car. Have it checked; Ford also sends a flashing TPMS light to the dealer.
How to reset the tire pressure light
It depends on the car, so check the owner’s manual. In some cases the light goes out after you drive a few miles with the problem fixed; in others the system needs calibrating, from a menu or button, after the tires are inflated or changed. Honda’s manual describes both, depending on what turned the light on.
The monitoring system is a warning, not a gauge check: federal rules require owner’s manuals to say it is not a substitute for proper tire maintenance (FMVSS 138), and the USTMA still checks with a gauge every month.
Questions people ask
Is it safe to drive with the tire pressure light on?
Only gently, and only as far as somewhere you can check the tires. The light means a tire is at least 25% low, and an under-inflated tire can overheat and fail (FMVSS 138, Honda).
Why is my tire pressure light on when the tires look fine?
A tire can be 25% low and still look normal, especially on a cold morning. Check with a gauge, not by eye.
Why is my tire pressure light flashing?
If it flashes for about a minute after you start the car and then stays on, the monitoring system has a fault (FMVSS 138, Honda). Have it checked.
What should my tire pressure be?
The pressure on the label on the driver’s door jamb, or in the owner’s manual (USTMA, Honda), checked when the tires are cold.
How long does it take for the tire pressure light to go off?
On some cars after a few miles of driving once the problem is fixed; others need the system calibrated from a button or menu (Honda). See your manual.
Sources
- FMVSS No. 138, Tire pressure monitoring systems (49 CFR 571.138): required since September 1, 2007; the light within 20 minutes at 25% below the recommended cold pressure; flashing 60–90 seconds for a malfunction; the owner’s manual statement on under-inflation and regular checks. FMVSS No. 101, Table 1: the low tire pressure symbol, in yellow.
- Honda, 2023 Integra Owner’s Manual, If the Low Tire Pressure/TPMS Indicator Comes On or Blinks: drive carefully; check and adjust the pressure to the door jamb label; blinking about a minute for a system problem or a compact spare; calibration.
- Ford, What do the warning and indicator lights in my Ford mean?: check pressure as soon as possible; a flashing light goes to the dealer.
- U.S. Tire Manufacturers Association, Tire Care Essentials: check monthly when cold (parked three hours); the label on the driver’s door; 1–2 pounds per 10 degrees; TPMS doesn’t replace gauge checks.
- Michelin, Prepare your car for winter: about 1 psi lost for every 10 °F drop; cold speeds up air loss.