Tyre pressure warning light: Everything you need to know

The tyre pressure warning light is designed to alert you when the air pressure in one or more of your tyres is too low.

This important car dashboard warning light is part of the tyre pressure monitoring system (TPMS), which helps to ensure your tyres maintain the correct air pressure levels for safety and performance.

Maintaining the correct tyre pressure is crucial for vehicle safety, prolonging tyre life, and ensuring optimal driving conditions. If your tyre pressure warning light switches on while you’re driving, this is a sign that your air pressure may be too low.

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What is a tyre pressure warning light?

In most cars, the tyre pressure warning light resembles a flat tyre with an exclamation mark in the middle.

This warning light is a key component of your vehicle’s TPMS, which continuously monitors the air pressure in each tyre. It is activated when the TPMS sensors detect that pressure has dropped to around 25% below the manufacturer’s recommended level in one or more tyres.

Common causes for the tyre pressure warning light

Low tyre pressure

If the light is working correctly, it should only illuminate when tyre pressure drops 25% or more below the recommended levels.
Temperature changes

Temperature fluctuations, caused by the weather, or heat generated by driving on a tyre may temporarily activate the tyre pressure warning light.
Faulty TPMS sensor

If the TPMS sensor is faulty, it may cause the tyre pressure warning light to illuminate incorrectly.
Objects in the tyre

The tyre pressure warning light may illuminate if there is a puncture or foreign object in a tyre.
Bent wheels or rims

These issues may also trigger the tyre pressure warning light.

Symptoms of low tyre pressure

Your vehicle is more difficult to handle than usual.
You experience a reduction in fuel efficiency.
Your tyres begin to wear unevenly.
You hear a flapping noise while driving.
You feel a lack of grip while driving.

Can you drive with the tyre pressure warning light on?

Yes, from a legal standpoint, you can drive when the tyre pressure warning light is on. However, you do need to drive cautiously (and at a reduced speed) to avoid causing further damage to your tyres.

As we discussed earlier, driving with low tyre pressure can make driving more dangerous, due to limited or difficult handling.

You might also notice your tyres wearing unevenly because of the extra pressure put on the treads. This can decrease traction and increase the risk of the vehicle slipping or sliding.

Keep driving until you can find a safe place to stop and check your tyres. If you don’t find a puncture, drive to the nearest petrol station to inflate them as soon as possible.

How to diagnose tyre pressure issues

Check the dashboard

If your car has a TPMS, your dashboard might indicate which specific tyre is low on air.
Check your tyres manually

Look for any visible signs of deflation, including sagging or bulging. Feel the tyres with your hand to check whether they are soft or hard. Older tyres will inevitably become harder.
Check steering response

If there are any sudden changes in your steering response, this might indicate reduced pressure.
Check for vibrations

If there are any vibrations within your car, this could also indicate that your tyre pressure is low.
Check for damage

Are there any screws wedged into the tyre, for example? If so, this will cause a leak.
Use a tyre pressure gauge

This will allow you to check the pressure of all four tyres effectively.

How to fix tyre pressure issues

If you discovered any damage or leaking whilst carrying out the steps above, have the affected tyres repaired or replaced (depending on the significance of the damage).
If you noticed that a TPMS sensor is faulty, you should have it checked by a mechanic and replaced where necessary.
Finally, if your tyres simply need reinflating, ensure you inflate them to the correct PSI (pounds per square inch). You can find tyre inflation machines at most petrol stations.

Tips for maintaining proper tyre pressure

Take note of the recommended PSI for your vehicle. You should be able to find this information in your vehicle handbook or online. This way, you’ll know if the pressure is too low or high when you check your tyres.
It’s best to check tyres when they are cold as opposed to when you’ve been driving on them. Driving warms up the tyres, which in turn increases pressure. So, checking them before you drive will provide you with a more accurate reading.
When you are checking the pressure with a gauge, be sure to use quality equipment. Whilst there are cheaper tyre pressure gauges available, you’ll probably find that the equipment at the petrol station will give a more accurate reading.
Be careful not to overload your vehicle, as this can reduce tyre pressure – and accelerate wear.
Regularly check your tyres for damage, including cracks or punctures.

Frequently Asked Questions

Yes, driving with low tyre pressure can cause damage to your car. It causes excessive wear and tear on your tyres, which, in turn, will interfere with your car’s handling and braking performance.

You should only drive as far as the nearest petrol station, where you can re-inflate your tyres to the appropriate pressure. Drive with caution- and at a reduced speed, as your car’s handling and performance will be compromised.

When your tyre warning light comes on, you should pull over to a safe place and manually check your tyres for damage.

If your tyres are merely underinflated, drive carefully to the nearest petrol station to re-inflate them. However, if any tyres have a puncture, call your breakdown provider and ask to be towed to a garage.

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