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:

    Immobilizer
    The immobilizer prevents your vehicle from being started without the correct SmartKey. When leaving the vehicle, always take the SmartKey with you and lock the vehicle. The engine can be starte ...

    Driving over obstacles
    Obstacles could damage the floor of the vehicle or components of the chassis. Ask passengers for guidance when driving over large obstacles. The passenger should always keep a safe distance fro ...

    The bodywork: A first: frameless, all-aluminium doors
    Intelligent lightweight construction plays a decisive role in bridging the classic conflict of objectives between low weight and high strength in the new CLS. The CLS is thus the first vehicle fro ...