If the tyre pressure is too low, the tyre's diameter is changed and, as a result, so is its rotation speed. By comparing the tyres with each other the system can determine whether one or more tyres have pressure that is too low.
The system does not replace normal tyre maintenance.
If the tyre pressure is too low then an indicator symbol () illuminates in the combined instrument panel and one of the following messages is shown:
- Tyre pressure low Check, adjust and calibrate
- Tyre pressure system Service required
- Tyre pressure system Currently unavailable
Deleting the messages
- Incorrect tyre pressure may lead to tyre failure, which could result in the driver losing control of the car.
- The system cannot indicate sudden tyre damage in advance.
In order for TM system to work correctly, a reference value for the tyre pressure must be determined. This must be done each time the tyres are changed or the tyre pressure is changed by recalibrating the system in MY CAR.
For example, the tyre pressure should be adjusted when driving with a heavy load or for high-speed driving (above 160 km/h (100 mph)). Following which, the system must be recalibrated.
The new reference value applies until steps 1-5 are repeated.
- After a tyre has been inflated, always refit the dust cap in order to avoid damage to the valve from gravel, dirt, etc.
- Only use plastic dust caps. Metal dust caps can rust and become difficult to unscrew.
System and tyre status
The status is colour-coded for each tyre in accordance with the following:
- All-green: the system is operating normally and the tyre pressure in all tyres is slightly above the recommended level.
- Yellow wheel: corresponding tyre's pressure is too low.
- All wheels yellow: two or more tyres have pressure that is too low.
- All wheels grey and the message Tyre pressure system Currently unavailable: the tyre pressure system is temporarily deactivated. It may be necessary to drive the car for a short time above 30 km/h (20 mph) before the system becomes active again.
- All wheels grey and the message Tyre pressure system Service required: an error has occurred in the system. Contact a Volvo dealer or workshop.