2011 Mercedes S-Class Owner's Manual - Page 489

Tire pressure Check the tire pressure at least once a month. Only check and correct tire pressures when the tires are cold (Y page 483). The tire pressure monitor has a yellow warning lamp in the instrument cluster for indicating pressure loss/malfunctions (USA) or pressure loss (Canada). Depending on how the warning lamp flashes or lights up, a tire pressure that is too low or a malfunction in the tire pressure monitor is displayed: Rif 487 Checking the tire pressures manually In order to determine and adjust the tire pressures, proceed as follows: X Tire pressure monitor Important safety notes If a tire pressure monitor is installed, the vehicle's wheels have sensors installed that monitor the tire pressures in all four tires. The tire pressure monitor warns you when the pressure drops in one or more of the tires. The tire pressure monitor only functions if the correct wheel electronics units are installed in all wheels. Z Tires and wheels Remove the valve cap of the tire you wish to check. X Press the tire pressure gauge securely onto the valve. X Read the tire pressure and compare it with the recommended value on the Tire and Loading Information placard on the B-pillar on the driver's side of your vehicle. X If necessary, increase the tire pressure to the recommended value (Y page 483). X If the tire pressure is too high, release air by pressing down the metal pin in the valve using the tip of a pen, for example. Then, check the tire pressure again using the tire pressure gauge. X Screw the valve cap onto the valve. X Repeat the steps for the other tires. the warning lamp is lit continuously, the tire pressure on one or more tires is significantly too low. The tire pressure monitor is not malfunctioning. RUSA only: if the warning lamp flashes for 60 seconds and then remains lit constantly, the tire pressure monitor is malfunctioning. G Warning Each tire, including the spare (if provided), should be checked at least once a month when cold and inflated to the inflation pressure recommended by the vehicle manufacturer on the Tire and Loading Information placard on the driver's door Bpillar or the tire inflation pressure label on the inside of the fuel filler flap. If your vehicle has tires of a different size than the size indicated on the Tire and Loading Information placard or the tire inflation pressure label, you should determine the proper tire inflation pressure for those tires. As an added safety feature, your vehicle has been equipped with a tire pressure monitoring system (TPMS) that illuminates a low tire pressure telltale when one or more of your tires are significantly underinflated. Accordingly, when the low tire pressure telltale illuminates, you should stop and check your tires as soon as possible, and inflate them to the proper pressure. Driving on a significantly underinflated tire causes the tire to overheat and can lead to tire failure. Underinflation also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling and stopping ability. Please note that the TPMS is not a substitute for proper tire maintenance, and it is the driver's responsibility to maintain correct tire pressure, even if underinflation has not