Tyre pressure warning light: what does it mean

Confused by the tyre pressure warning light? This guide shows you what it means and the simple steps to get rid of it.

The tyre pressure warning light is more than a dashboard nuisance: it signals low or uneven tyre pressure, which can affect safety, fuel efficiency, and tyre life. This handy guide explains how to deal with a tyre pressure warning light and shows how to reset the tyre pressure warning light after addressing the cause. With these tips, you’ll quickly restore proper tyre pressure and keep your car running safely.

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What is the tyre pressure warning light?

The tyre pressure warning light is a small amber icon on your car dashboard that pops up when one or more tyres are under-inflated. It’s your car’s way of saying your tyres need attention, since low pressure can affect handling, wear, and safety. Think of it as a quick heads-up to check your tyres before it becomes a bigger problem.

Why does the tyre pressure warning light turn on?

There are a few reasons why the tyre pressure warning light turns on. Here’s a quick rundown of the most common causes:

Low pressure

Most of the time, that tyre pressure warning light isn’t playing tricks – your tyres are actually low. Cars usually trigger the light when pressures drop below about 75% of the recommended level, so you’ve usually got time to fix it.

Driving on under-inflated tyres can wear them out faster, eat more fuel, and make your car feel less stable, so it’s a good habit to check your pressures regularly and stay safe on the road.

Temperature fluctuations

Ever notice your tyre pressure warning light come on after a chilly night? That’s usually just the cold air causing tyre pressure to drop – air contracts when it’s cold, so your tyres naturally lose a bit of pressure.

The fix is simple: check your tyre pressures and top them up if needed, or just go for a short drive to warm the tyres up and the light should turn off.

TPMS system fault

Sometimes the tyre pressure warning light sticks around even after you’ve pumped your tyres to the right pressure: this could be a TPMS system fault. Usually, a faulty sensor will flash for a bit before staying on (check your vehicle’s handbook, since every car is different). Either way, it’s worth double-checking this.

An object is wedged in your tyre

Sometimes the tyre pressure warning light comes on because something is stuck in your tyre, such as a nail or a sharp stone. If you notice your tyre keeps losing pressure, take a close look at the tread to see if anything is poking out. Catching it early can save you from a flat or bigger damage down the road.

What to do when the warning light comes on?

When the tyre pressure warning light comes on, the first thing to do is safely pull over and check your tyres. Use a pressure gauge to see if any tyres are under-inflated and top them up to the manufacturer’s recommended levels (check your manual for this). If the light stays on after adjusting the pressures, there could be a TPMS sensor issue, so it’s a good idea to have your car checked by a professional.

How to reset the tyre pressure warning light

To reset the tyre pressure warning light, first make sure all your tyres are pumped up to the correct pressure. Then, either hold down the TPMS reset button (this is usually under the steering wheel) or use your car’s infotainment system to find the “TPMS” or “tyre pressure” option. Once you hit reset, just drive for 10-20 minutes and the system should recalibrate itself.

Tyre pressure warning light FAQs

Can I drive if the tyre pressure warning light is on?

Yes, you can drive with the tyre pressure warning light on, but only for a short distance and very carefully. Keep your speed low, avoid sharp turns or sudden braking, and head straight to a safe spot to check and inflate your tyres. If a tyre is completely flat, don’t try to drive on it: use your spare or call for roadside assistance.

Is the tyre pressure okay if the warning light isn’t on?

No, not having the tyre pressure warning light on doesn’t always mean your tyres are at the right pressure. The system can sometimes miss small drops or even malfunction. The safest approach is to check your tyre pressure regularly with a gauge and make sure it matches the manufacturer’s recommended levels. This can usually be found on a sticker inside the driver’s side door.

Can a car fail its MOT with a faulty tyre pressure warning light?

Yes, a car can fail its MOT if the tyre pressure warning light is faulty. This applies to vehicles registered on or after 1 January 2012, since TPMS is a required part of the test. If the light flashes or stays on, showing a system fault, the car won’t pass until the issue is fixed and the warning light turns off.

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