Vehicle care 201If problems occur during the relearnprocess a warning message isdisplayed in the Driver InformationCentre.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 Centre 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 periodically. Ensure thatthe direction of rotation of the wheelsis the same as before.Tyres age, even if they are not used.We recommend tyre replacementevery 6 years.Changing tyre and wheelsizeIf tyres of a different size than thosefitted at the factory are used, it may benecessary to reprogramme thespeedometer as well as the nominaltyre pressure and make other vehiclemodifications.After converting to a different tyresize, have the label with tyrepressures replaced.9 WarningUse of unsuitable tyres or wheelsmay lead to accidents and willinvalidate the vehicle typeapproval.Wheel coversWheel covers and tyres that arefactory approved for the respectivevehicle and comply with all of therelevant wheel and tyre combinationrequirements must be used.
