See also:

Problems with the SmartKey
Problem Possible causes/consequences and Solutions You cannot lock or unlock the vehicle using the SmartKey. The SmartKey battery is discharged or nearly discharged. - ...

115 V power socket
WARNING   The 115V AC socket operates at high voltage. Use the 115V AC socket in the vehicle with the same caution and prudence that you exercise when using power outlets at home. Keep ...

Safety & Features
As of this writing, neither the National Highway Traffic Safety Administration nor the Insurance Institute for Highway Safety has tested the E-Class wagon. (IIHS has tested the E-Class sedan, but ...