See also:

General notes
If you cannot lock or unlock the vehicle with the SmartKey, either the battery in the SmartKey is discharged, the SmartKey is faulty or the starter battery is discharged. - Check the battery in ...

Charging the battery
WARNING Never charge a battery still installed in the vehicle unless a battery charger unit approved by Mercedes-Benz is being used. Gases may escape during charging and cause explosions th ...

Checking tire pressure electronically
Make sure that the SmartKey is in position 2 () in the ignition lock. Press the or button on the steering wheel to select the Service menu. Press the or button to select Tire Pres ...