What the TPMS light means and what you need to do
The tyre pressure monitoring system (TPMS) light is a warning indicator on the dashboard that tells you when your tyres are too low. The light is a picture of the cross-section of a tyre (shaped like a horseshoe) with an exclamation mark inside it. TPMS has been fitted to vehicles for many years however, in November 2012, the European Union passed a law requiring that all new models of passenger vehicles (cars and trucks) sold in the EU must be equipped with a TPMS system and broadened the legislation in November 2014 to every new passenger vehicle. A TPMS system is not a substitute for checking your tyre pressure regularly.
At what pressure does the TPMS light come on?
The TPMS is required to warn the driver of cars and light trucks when tyre pressure falls below a certain threshold of the manufacturers recommended pressure for that vehicle. The recommended pressure value varies from vehicle to vehicle and usually is available in the car’s manual, a sticker on the driver’s side doorpost or the inside the fuel filler flap.
How do I get the TPMS light to go off?
If you have inflated your tyres to the correct pressure but the TPMS is still on, always refer to your vehicle manual for instructions on how to reset the TPMS system, or consult a tyre professional. For some vehicles by driving your car for around 10 minutes, stopping the car, turning it off and back on again may rest the TPMS systems and turn the light off.
Can you drive with the TPMS light on?
The TPMS exists for safety reasons, so when it indicates a problem, you should heed it and check your tyres’ pressure. If you check the pressure of your tyres (including your spare if it has a TPMS sensor) when they are cold (some tyre manufacturers recommend two or more hours since they were driven on) and they are all at the recommended pressure, this may mean that your TPMS is not functioning properly. If this is the case, it may be safe to drive on them but you should fix the issue as soon as possible or contact a tyre service professional. It is important to have a properly functioning TPMS so it can alert you if your tyre pressure falls below the tolerance set of the correct pressure.
What is the difference between TPMS and proper tyre pressure?
Essentially, TPMS is a warning system that alerts you when your tyre is below a certain threshold of the recommended pressure. Low tyre pressure is one of the mechanical conditions that the TPMS warns you about (can also be an imbalance across the vehicles tyre pressures). Your tyres can be below the actual recommended pressures without dropping below the tolerance set for the warning system, so it is important to check your tyre pressure monthly and before long trips. When the TPMS signal lights up on your dashboard, this means that your tyre pressure below the set threshold of the proper recommended pressure.
Winter tyres
TPMS light goes on and off
Temperature changes can influence tyre pressure, as hotter air expands and colder air contracts. If one or more of your tyres is close to the minimum or maximum threshold for triggering the warning, temperature fluctuations caused by seasonal or daily changes or the heat generated by driving on a tyre can be enough to temporarily activate the TPMS warning light. To address the issue, check all of the tyres when cold and adjust the pressure to the recommended value. This should bring the pressure values close enough to the recommended ones so that temperature swings will no longer be enough to set off the TPMS.
TPMS light flashes and then stays on
If the TPMS light flashes when you start up the car and then stays on, this usually means that one of your TPMS sensors is faulty. In this situation, you should take your car into a garage as soon as possible to have the problem fixed however before doing so always manually check your tyre pressures to make sure the vehicle can be driven safely.
Does TPMS replace regular tyre pressure checks?
Tyre pressure monitoring systems indicate you when one or more of your tyres have a loss in pressure. Low pressure can lead to tyre damage, difficulty controlling the vehicle, accelerated tyre wear or even a complete failure of the tyre/tyres. Whether or not your vehicle has TPMS it is still important to do regular air pressure checks because your tyres can still be moderately underinflated or overinflated if the TPMS light indicator does not come on. Even moderate deviations in tyre pressure can cause damage to your tyre, impact your fuel mileage and the life of your tread, and diminish your vehicle’s braking, cornering and handling abilities.
What happens when I don’t use the proper tyre pressure?
You should always try to keep your tyres inflated to the pressure recommended by your vehicle manufacturer. Tyres used in an underinflated state, can lead to the tyre’s sidewalls can flexing and damage occurring to the belting structure in the tyres. You may not be able to see this damage, which can increase over time. This is why you should maintain proper inflation pressure and avoid driving when the TPMS light is on. If you absolutely must drive a short distance on a tyre with severely low pressure, drive very slowly and use extreme caution. The tyre should be inflated or changed before driving anywhere.
FAQs
The location of the TPMS reset varies from model to model. Look in your vehicles owner manual to find out where the exact location is in your vehicle. Common locations are under the steering wheel, or on the dashboard however on many vehicles you will have to access the vehicle on board computer to reset the pressure values.
While TPMS systems in the UK are not required to notify you of over inflation, many do. Consult your owner’s manual for more information.
There are two types of Tyre pressure monitoring systems, indirect (uses an ABS system to monitor the speed of the wheel) and direct (sensors inside the wheel to report pressure data to the vehicle's ECU in real time) either of the systems can be used as a requirement of the legislation. There are very few situations where it makes sense to try to fix a TPMS other than routine servicing for a direct system. Direct sensors usually go faulty because the non-replaceable battery has run down; if this occurs, a new sensor will need to replace the old to rectify the issue.
Nearest dealer
If you still have questions about your tyre pressure or you need to fix a tyre, get help from your nearest tyre dealer so you can stay safe on the road.
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