Key
Important safety notes
United Kingdom only: G
WARNING
When the double locks are activated, the
doors can no longer be opened from the
inside. People in the vehicle can no longer get out, e.g. in hazardous situations. There is a
risk of injury.
Therefore, do not leave any people unsuper-
vised in the vehicle, particularly children, eld-
erly people or people in need of special assis-
tance. Do not activate the double lock when
people are in the vehicle.
If the vehicle has been locked from the outside, the double lock function is activated as stand-
ard. It is then not possible to open the doors
from inside the vehicle. You can deactivate the
double lock function by deactivating the interior
motion sensor (see Digital Owner's Manual).
The doors can then be opened from the inside
after the vehicle has been locked from the out-
side. The anti-theft alarm system is triggered if
the door is opened from the inside. Switch off
the alarm (Y page 78).
All countries: G
WARNING
If children are left unsupervised in the vehicle, they could:
R open doors, thereby endangering other per-
sons or road users
R get out and be struck by oncoming traffic
R operate vehicle equipment and become
trapped, for example
In addition, the children could also set the
vehicle in motion, for example, if they:
R release the parking brake
R shift the automatic transmission out of park
position P or shift manual transmission into
neutral
R start the engine
There is a risk of an accident and injury. When leaving the vehicle, always take the key
with you and lock the vehicle. Never leave
children and animals unattended in the vehi-
cle. Keep the keys out of the reach of children. G
WARNING
If you attach heavy or large objects to the key, the key could be unintentionally turned in the
ignition lock. This could cause the engine to
be switched off. There is a risk of an accident.
Do not attach any heavy or large objects to the
key. Remove any bulky keyrings before insert-
ing the key into the ignition lock.
! Keep the key away from strong magnetic
fields. Otherwise, the remote control function could be affected.
Strong magnetic fields can occur in the vicin-
ity of powerful electrical installations.
Do not keep the key: R with electronic devices, e.g. a mobile phone
or another key
R with metallic objects, e.g. coins or metal foil
R inside metallic objects, e.g. a metal case
This can impair the key's function.
Vehicles with KEYLESS-GO start function: do
not keep the key in the boot. Otherwise, the key
may not be detected, e.g. when starting the
engine using the Start/Stop button.
A check that periodically establishes a radio
connection between the vehicle and the key
determines whether a valid key is in or in the
direct vicinity of the vehicle. This occurs, for
example:
R during engine start
R during driving
R when the external door handles are touched
R during convenience closing Key
81Opening and closing Z
Problem
Possible causes/consequences and
M
MSolutions You can no longer lock or
unlock the vehicle using
KEYLESS-GO. KEYLESS-GO has been deactivated.
X Reactivate KEYLESS-GO (Y page 82). The key battery is weak or discharged.
X Check the key battery (Y page 84) and replace if necessary
(Y page 84).
If this does not work: X Lock or unlock the vehicle using the emergency key element
(Y page 89). Interference from a powerful source of radio waves.
X Lock or unlock the vehicle using the emergency key element
(Y page 89). Fault with KEYLESS-GO.
X Lock or unlock the vehicle using the remote control function of the
key.
X Have the vehicle and key checked at a qualified specialist work-
shop.
If the vehicle cannot be locked or unlocked even using the remote
control function:
X Lock or unlock the vehicle using the emergency key element
(Y page 89).
X Have the vehicle and key checked at a qualified specialist work-
shop. The engine cannot be
started using the key. The on-board voltage is too low.
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary (Y page 332).
or X Jump-start the vehicle (Y page 333).
or X Consult a qualified specialist workshop. The engine cannot be
started using the Start/
Stop button. The key is in
the vehicle. The vehicle is locked.
X Unlock the vehicle and try to start the vehicle again. The key battery is weak or discharged.
X Check the key battery (Y page 84) and replace if necessary
(Y page 84).
If this does not work: X Start your vehicle with the key in the ignition lock. Interference from a powerful source of radio waves.
X Start your vehicle with the key in the ignition lock. 86
KeyOpening and closing
for example, the power steering and the brake
boosting effect. You will require considerably
more effort to steer and brake. There is a risk of an accident.
Do not switch off the ignition while driving. G
WARNING
If the parking brake has not been fully
released when driving, the parking brake can:
R overheat and cause a fire
R lose its hold function.
There is a risk of fire and an accident. Release
the parking brake fully before driving off.
! Do not warm up the engine when the vehicle
is stationary. Drive off immediately. Avoid
high engine speeds and driving at full throttle
until the engine has reached its operating
temperature.
Only shift the automatic transmission to the
desired drive position when the vehicle is sta-
tionary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery roads.
You could otherwise damage the drive train. Key positions
Key g
To remove the key
1 Power supply for some consumers, such as
the windscreen wipers
2 Ignition (power supply for all consumers)
and drive position
3 Starting the vehicle i
If the key does not belong to the vehicle, it
can still be turned in the ignition lock. How-
ever, the ignition will not be switched on. The
engine cannot be started.
Start/Stop button General notes
When you insert the Start/Stop button in the
ignition lock, the system needs approximately
two seconds of recognition time. You can then
use the Start/Stop button.
Pressing the Start/Stop button several times in succession corresponds to the different key
positions in the ignition lock. This is the case
only if you are not depressing the brake pedal.
If you depress the brake pedal and press the
Start/Stop button, the engine starts immedi-
ately.
A check that periodically establishes a radio
connection between the vehicle and the key
determines whether a valid key is in the vehicle.
This occurs, for example, when the engine is
started.
To start the vehicle without actively using the
key:
R the Start/Stop button must be inserted in the
ignition lock
R the key must be in the vehicle
R the vehicle must not be locked with the key or
KEYLESS-GO (Y page 82)
Do not keep the key:
R with electronic devices, e.g. a mobile phone
or another key
R with metallic objects, e.g. coins or metal foil
R inside metallic objects, e.g. a metal case
This can impair the key's function.
If you lock the vehicle with the key's remote
control or with KEYLESS-GO, after a short time:
R you will no longer be able to switch on the
ignition with the Start/Stop button
R you will no longer be able to start the engine
with the Start/Stop button until the vehicle is
unlocked again
If you lock the vehicle centrally using the button
on the front door (Y page 88), you can continue
to start the engine with the Start/Stop button.
You can switch off the engine while the vehicle is
in motion by pressing and holding the Start/
Stop button for around three seconds. This func- Driving
133Driving and parking Z