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.

replace it if necessary. Check the battery in the SmartKey and replace it if necessary.
mechanical key. Unlock the driver's door using the mechanical key.
Lock the vehicle.
contacts checked at a qualified specialist Have the starter battery and the battery contacts checked at a qualified specialist workshop.

If the SmartKey is faulty, contact Roadside Assistance or a qualified specialist workshop.

    See also:

    4MATIC (permanent four-wheel drive)
    4MATIC ensures that all four wheels are permanently driven. Together with ESP® and ETS, it improves the traction of your vehicle whenever a drive wheel spins due to insufficient grip. WARNIN ...

    Problems with the engine
    ...

    Clearing the memory of the integrated garage door opener on the rear-view mirror
    Turn the SmartKey to position 2 in the ignition lock. Press transmitter buttons 2 and 4. The indicator lamp lights up yellow. Press and hold transmitter buttons 2 and 4 until the indic ...