Vehicle care 181The tyre pressure monitoring systemvalve cores and sealing rings must bereplaced each time the tyres arechanged.Adaptive threshold functionThe tyre pressure monitoring systemautomatically detects if the vehicle isdriven with a tyre pressureappropriate for a load of up to3 people or for a full load.If the tyre pressure must be reduced,switch off ignition first.Auto learn functionAfter changing wheels the vehicle hasto be stationary for approx.20 minutes before the systemrecalculates. The following relearnprocess takes up to 10 minutes ofdriving with a minimum speed of12 mph (20 km/h). In this case $ canbe displayed or pressure values canswap in the Driver Information Center.If problems occur during the relearnprocess a warning message isdisplayed in the Driver InformationCenter.Temperature compensationCold tyres decrease the tyrepressure, warm tyres increase thetyre pressure. The tyre pressuremonitoring system considers thiseffect for the warning messages.The tyre pressure value displayed inthe Driver Information Center showsthe actual tyre pressure. Therefore itis important to check tyre pressurewith cold tyres.Tread depthCheck tread depth at regularintervals.Tyres should be replaced for safetyreasons at a tread depth of 2-3 mm(4 mm for winter tyres).The legally permissible minimumtread depth (1.6 mm) has beenreached when the tread has worndown as far as one of the tread wearindicators (TWI). Their position isindicated by markings on thesidewall.If there is more wear at the front thanthe rear, swap round front wheels andrear wheels. Ensure that the directionof rotation of the wheels is the sameas before.Tyres age, even if they are not used.We recommend tyre replacementevery 6 years.
