TPMS stands for tyre pressure monitoring system, it consists of small electric sensors fitted to each wheel of the vehicle to monitor tyre pressure and feed this data back to the car. Should one or more tyre see a change in air pressure, the system will show a yellow warning light on the dashboard to alert the driver. All new cars in the UK manufactured after 2014 are fitted with TPMS and any vehicle with a faulty or inoperative system will fail its MOT test.
Having TPMS fitted to your vehicle provides the following safety and handling benefits:
TPMS works by monitoring tyre pressures with sensors – if the pressure changes above or below a certain point an alert is shown on the dashboard. There are two different types of pressure monitoring systems – direct and indirect that work differently.
Direct TPMS works via air pressure sensors in each wheel on the valve of the tyre, that monitor the pressure within the tyre – these systems are usually able to provide these real time readings for each tyre along with temperatures. The system then transmits this information wirelessly to the car which creates an alert on the dashboard should the pressure change.
Provides a reading on the actual tyre pressure
Easier to damage sesnors during changing/maintenance of the tyre
Better acurracy of reading
Expensive system in comparison to indirect
Does not require a reset following tyre inflation or rotation
Lifetime of sensor/battery lasts longer
Indirect TPMS works differently, without the use of air pressure sensors in the tyres. Indirect systems detect a loss in pressure using the ABS wheel speed sensors to read the relative wheel speed to create pressure readings to compare between all 4 tyres. The theory behind this system is that once a tyre is under-inflated it begins to rotate faster than expected – which will then lead to an alert being sent to the dashboard.
System is cheaper than direct TPMS
Does not provide an accurate reading of tyre pressure
Needs less system calibrated or maintenance compared to direct systems
May provide incorrect reading if new tyres are different sizes
Requires resetting after tyre maintenance – rotation, inflation, etc.
TPMS is now a mandatory fitment in all new vehicles in the UK as of 2014. From 2015 onwards inoperative or faulty TPMS sensors would lead to a failed MOT.
If your vehicle is 2014 or newer it is likely to have TPMS. You can check if you have TPMS by checking for the TPMS light when turning your key in the ignition without starting the engine – causing all dashboard lights to show. If you have RunOnFlat or Run Flat tyres, you’ll also have TPMS. The owner’s manual will also detail if you have TPMS and which system.
TPMS can be serviced by your local tyre dealer – especially when fitting new tyres to ensure that the system is calibrated correctly to the right tyre size and recommended pressures. Tyre pressures should also be checked manually on a regular basis as well as carrying out checks on the general health of the tyre such as tread and sidewalls, a guide to this can be found here.
If your TPMS light comes on whilst driving you should stop as soon as it is safe to do so in order to check the tyre pressure of all of your tyres manually using a gauge to identify which tyre is having pressure issues in order to decide if a tyre change is needed or whether it is safest to head to the nearest garage.
