2008 Mercedes SL-Class Owner's Manual - Page 310

Operation Tires and wheels i Possible differences between the readings of a tire pressure gauge of an air hose, e.g. gas station equipment, and the vehicle's control system can occur. Usually the readings issued by the control system are more precise. Switch on the ignition ( page 40). Press button j or k until the current inflation pressures for each tire appear in the multifunction display. Warning! G Warning! G It is the driver's responsibility to calibrate the TPMS on the recommended cold inflation pressure. Underinflated tires affect the ability to steer or brake the vehicle. You might lose control over the vehicle. i With a spare wheel mounted, the system may still indicate the tire inflation pressure of the removed road wheel for some minutes. If this happens, keep in mind that the indicated value where the spare wheel is mounted does not reflect the actual spare tire inflation pressure. The TPMS does not indicate a warning for wrongly selected inflation pressures. Always adjust tire inflation pressure according to the Tire and Loading Information placard on the driver's door B-pillar or, if available, the supplemental tire inflation pressure information on the inside of the fuel filler flap. The TPMS is not able to issue a warning due to a sudden dramatic loss of pressure (e.g. tire blowout caused by a foreign object). In this case bring the vehicle to a halt by carefully applying the brakes and avoiding abrupt steering maneuvers. i When the vehicle has been parked for longer than 20 minutes, the message Tire pressure displayed after driving for a few minutes. appears in the multifunction display. 309