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.

SmartKey and 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.
mechanical key. Lock the vehicle using the mechanical key.
battery contacts checked at a qualified specialist workshop. 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:

    Engine
    Display messages   Top Up Coolant See Operator's Manual Possible causes/consequences and ► Solutions The coolant level is too low. ► Add coolant, observing the warning notes ...

    KEYLESS-GO
    General information Vehicles with KEYLESS-GO are equipped with a SmartKey featuring an integrated KEYLESSGO function and a detachable Start/Stop button. The Start/Stop button must be inserted ...

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