Tyre pressure monitoring uses sensors located inside the air valve in each wheel. When the car is driven at about 40 km/h the system detects the tyre pressure. If the pressure is too low then a warning lamp 
in the combined instrument panel illuminates and a message is shown in the information display.
Both factory-fitted and optional wheels can be fitted with TPMS sensors in the valves.
If wheels without TPMS sensors are used or if a sensor has failed then Tyre press. syst Service required will be shown.
Always check the system after changing a wheel in order to ensure that replacement wheels work with the system.
For information on the correct tyre pressure, see Tyres - air pressure.
The system does not replace normal tyre maintenance.
Important
If a fault should arise in the tyre pressure system a warning lamp in the combined instrument panel will illuminate and a message will be shown. This can be for various reasons, e.g. fitting a wheel not equipped with a sensor adapted for Volvo's tyre pressure monitoring system.
in the combined instrument panel will illuminate and a message will be shown. This can be for various reasons, e.g. fitting a wheel not equipped with a sensor adapted for Volvo's tyre pressure monitoring system.