2005 Mercedes E-Class Owner's Manual - Page 324

Operation Tires and wheels Checking tire inflation pressure Regularly check your tire inflation pressure at least once a month. Check and adjust the tire inflation pressure when the tires are cold. The tires can be considered cold if the vehicle has been parked for at least three hours or driven less than one mile (1.6 km). If you check the tire inflation pressure when the tires are warm (the vehicle has been driven for several miles or sitting less than three hours), the reading will be approximately 4 psi (0.3 bar) higher than the cold reading. This is normal. Do not let air out to match the specified cold tire inflation pressure. Otherwise, the tire will be underinflated. Checking tire inflation pressure manually Follow the steps below to achieve correct tire inflation pressure: Remove the cap from the valve on one tire. Firmly press a tire gauge onto the valve. Read tire inflation pressure on tire gauge and check against the recommended tire inflation pressure on the placard on the driver's door B-pillar ( page 315). If necessary, add air to achieve the recommended tire inflation pressure. Checking tire inflation pressure electronically* The tire pressure monitoring system 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. You can call up the tire inflation pressure using the control system ( page 150). 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. i After you have reactivated the tire pressure monitoring system, the current tire inflation pressures will only be shown after a few minutes' driving time. During this time, you will see the following message in the display: Tire pressure displayed only after driving a few mins. 322