2008 Mercedes S-Class Owner's Manual - Page 562

Operation Tires and wheels i If you have overfilled the tire, release tire inflation pressure by pushing the metal stem of the valve with e.g. a tip of a pen. Then recheck the tire inflation pressure with the tire gauge. Install the valve cap. Repeat this procedure for each tire. Checking tire inflation pressure electronically with the Advanced Tire Pressure Monitoring System (Advanced TPMS)*, (standard on U.S. vehicles) i USA only: This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. Any unauthorized modification to this device could void the user's authority to operate the equipment. The TPMS only functions on wheels that are equipped with the proper electronic sensors. It monitors the tire inflation pressure, as selected by the driver, in all four tires. A warning is issued to alert you to a decrease in pressure in one or more of the tires. Tire inflation pressure inquiries are made using the multifunction display. The present inflation pressures are displayed only after a few minutes of travel time. i The Advanced Tire Pressure Monitoring System (Advanced TPMS) is equipped with a combination low tire pressure/TPMS malfunction telltale in the instrument cluster ( page 608). Depending on how the telltale illuminates, it indicates a low tire inflation pressure condition or a malfunction in the TPMS system itself: If the telltale illuminates continuously, one or more of your tires is significantly under-inflated. There is no malfunction in the TPMS. USA only: If the telltale flashes for 60 seconds and then stays illuminated, the TPMS system itself is not operating properly. i Canada only: This device complies with RSS-210 of Industry Canada. Operation is subject to the following two conditions: (1) This device may not cause interference, and (2) this device must accept any interference received, including interference that may cause undesired operation of the device. Any unauthorized modification to this device could void the user's authority to operate the equipment. i Possible differences between the readings of a tire inflation 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. i The menu overview can be found on ( page 266). Switch on the ignition ( page 344). Press ( or & to select the menu "Service". Press $ or % to select "Tire pressure". Press #. 561