A Tyre Pressure Monitoring System or TPMS system is designed to monitor the air pressure inside your tyres. It's real-time tyre pressure information to the driver either via a gauge, a pictogram display or a warning light depending on the system fitted.

TPMS can be divided into two different types - direct and indirect. Direct TPMS uses pressure sensors on the tyre to physically measure the tyre pressure, whilst indirect TPMS uses other vehicle sensers such as ABS to compare wheel speeds.

From November 2012 new EU legislation requires that all car manufacturers are required to fit the TPMS system as standard to all new vehicles, aiding drivers to ensure that their tyres are at the correct pressure for optimised safety.

Some manufacturers already fit the TPMS system - for example if you have RunOnFlat tyres then this system will be fitted as a mandatory requirement at the time of your cars manufacture - but it is also possible to fit a TPMS system as an aftermarket product.

Once fitted, quite simply the system tells you if the pressure falls below the recommended level. On most systems when pressures fail the system will show a red warning icon on your dashboard to tell you that the pressure or temperature has moved to a potentially hazardous level, but this display could be different if you've fitted the system as an aftermarket product.

Why Are Air Pressures Important?

If you've read our other Tyre Handy Guides then you'll already know that regular checking of tyre pressures is required for a number of reasons:

  • To keep you safer
  • To increase the life of your tyre
  • To improve fuel economy

But let's look at these points in a little more detail...


The behaviour of a tyre is connected to its inflation pressure, key actions such as braking and stability require the inflation pressures to be adjusted and kept as specified by the vehicle manufacturer.

Under-inflation can even lead to thermal and mechanical overload of the tyre and as it overheats and in extreme cases it can lead to sudden destruction of the tyre itself.

Tyre Life and Fuel Economy.

Fuel efficiency and tyre wear are affected by under-inflation. Tyres naturally leak air over time, especially in warmer weather, which is why it's so important to check them regularly.

Check Your Tyre Pressure.

Always be sure your tyres are at the correct pressure, especially before you set out on a long journey, as under-inflation can cause rapid and uneven tread wear as we've already mentioned. Check the pressures when your tyres are cold i.e. you have driven less than two miles.

You'll find an easy to use table in your vehicle's manufacturers handbook telling you the correct pressures for your vehicle. Often this is also displayed on the arch of the driver's door of your vehicle. You can use a tyre pressure gauge or most petrol stations have a facility for you to check you pressures free of charge.

It is also useful to clean valves and check for leakage, you should also look to replace missing valve caps. And whilst your checking don't forget to include your spare, just in case.