Tire pressure light: why it stays on and how to reset it
Updated · Autofy
Tire pressure light: why it stays on and how to reset it
The amber light shaped like a tire with an exclamation mark means at least one tire has lost pressure. Check all four tires cold, inflate to the values on the sticker in the driver's door frame or fuel flap, then reset the system if your car requires it. A light that flashes for about a minute and then stays on usually points to a fault in the monitoring system itself, often a sensor battery.
What this light monitors
Since November 2014, every new car sold in the European Union must have a tire pressure monitoring system (TPMS). The US has required them since the late 2000s. There are two kinds:
- Direct: a sensor in each valve measures pressure and sends it to the car, often showing which tire is affected.
- Indirect: no sensor in the wheel; the car compares wheel speeds using the ABS sensors. An under-inflated tire is smaller, so it spins faster.
What to do when it comes on
- Slow down and look at your tires as soon as you can stop safely. A flat or very soft tire: don't drive, fit the spare or call for assistance.
- Inflate all four tires at a station, cold, to the values on the sticker in the driver's door frame or fuel flap. The pressure often depends on the load.
- Reset the system if your car asks for it (dedicated button or onboard menu). It's essential on indirect systems.
- Light back a few days later? Probably a slow puncture: a nail or a leaking valve. Get it checked.
Steady or flashing
- Steady: pressure too low on at least one tire.
- Flashes for about a minute, then stays on: system fault. A sensor with a flat battery (they last several years, not forever), a sensor broken during fitting, or winter wheels without sensors.
Why it matters
An under-inflated tire brakes worse, grips less, wears faster on the edges and increases fuel use. It also runs hotter, which raises the risk of a blowout on the motorway. Checking pressures once a month and before a long trip remains the best habit, light or no light.
Wear is checked separately: the legal minimum tread depth in Europe and the UK is 1.6 mm, and our guide when to replace your tires covers the other signs.
Keep track of your tires
Autofy tracks your tires with a gauge based on their mileage and age, and keeps a record of every fitting. Every other light is in our dashboard warning lights guide.