2012 MERCEDES-BENZ E-CLASS CABRIOLET change key battery

Changing the settings of the locking
system
You can change the settings of the locking
system. This means that only the driver's door
and the fuel fille rflap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel on your own.
X To change the setting: press and hold
down the %and& buttons on the
key simultaneously for approximately six
seconds until the battery chec klamp
flashes twice ( Ypage 79).
i If the setting of the locking system is
changed within the signal range of the vehi-
cle, pressing the &or% button:
R locks or
R unlocks the vehicle
The key now functions as follows:
X To unlock the driver's door: press the
% button once.
X To unlock centrally: press the%but-
ton twice.
X To lock centrally: press the&button.
The KEYLESS-GO function is changed as fol-
lows:
X To unlock the driver's door: touch the
inner surface of the door handle on the
driver's door.
X To unlock centrally: touch the inner sur-
face of the front-passenger door handle.
X To lock centrally: touch the outer sensor
surface on one of the door handles.
X To restore the factory settings: press
and hold down the %and& buttons
simultaneously for approximately six sec-
onds until the battery check lamp flashes
twice (Y page 79). Emergency key element
General notes If the vehicle can no longer be locked or
unlocked with the key, use the emergency
key element.
If you use the emergenc
ykey element to
unlock and open the driver's door or the boot
lid, the anti-thef talarm system will be trig-
gered (Y page 71).
There are several ways to tur noff the alarm:
X To turn the alarm off with the key: press
the % or& button on the key.
or
X Insert the key into the ignition lock.
or
X To deactivate the alarm with KEYLESS-
GO: press the Start/Stop button in the igni-
tion lock. The key must be in the vehicle.
or
X Lock or unlock the vehicle using KEYLESS-
GO. The key must be outside the vehicle.
Removing the emergency key element :
Release catch
; Emergency key element
X Push release catch :in the direction of
the arrow and at the same time, remove
emergency key element ;from the key. 78
KeyOpening and closing

Battery of the key
Important safety notes G
WARNING
Batteries are toxic and contain caustic sub-
stances. For this reason, keep batteries ou tof
the reach of children.
If a battery has been swallowed, visit a doctor
immediately. H
Environmental note Batteries contain pollutants.
It is illegal to dispose of them
with the household rubbish.
They must be collected sep-
arately and disposed of in an
environmentally responsible
recycling system.
Dispose of batteries in an
environmentally responsible
manner. Take discharged
batteries to a qualified spe-
cialist workshop or to a col-
lectio npoint for used batter-
ies.
Mercedes-Benz recommends that you have
the batteries replaced at a qualified specialist
workshop.
Checking the battery X
Press the &or% button.
The battery is working properly if battery
check lamp :lights up briefly. The battery is discharged if battery check
lamp
:does not light up briefly.
X Change the battery (Y page 79).
i If the key battery is checked within the
signal reception range of the vehicle, press-
ing the &or% button:
R locks or
R unlocks the vehicle
i You can get a battery in any qualified spe-
cialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery.
X
Take the emergency key element out of the
key (Y page 78). :
Battery compartment cover
; Emergency key element
X Press emergency key element ;into the
opening in the key in the direction of the
arrow until battery compartment cover :
opens. When doing so, do not hold battery
compartment cover :shut.
X Remove battery compartment cover :. Key
79Opening and closing Z

Problems with the key
Problem Possible causes/consequences and
M Solutions
You cannot lock or
unlock the vehicle
using the key. The key battery is discharged or nearly discharged.
X
Try again to lock/unlock the vehicle using the remote control
function of the key. Point the tip of the key at the driver's door
handle from close range and press the %or& button.
If this does not work:
X Check the key battery (Y page 79) and replace it if necessary
(Y page 79).
X Lock (Y page 84) or unlock (Y page 84) the vehicle using
the emergency key element. The key is faulty.
X
Lock (Y page 84) or unlock (Y page 84) the vehicle using
the emergency key element.
X Have the key checked at a qualified specialist workshop. You can no longer lock
or unlock the vehicle
using KEYLESS-GO. KEYLESS-GO is in standby mode because the vehicle has not been
unlocked for an extended period.
X
Pull the door handle and then turn the key to position 2in the
ignition lock. There is interference from a powerful source of radio waves.
X Lock/unlock the vehicle using the remote control function of
the key. Point the tip of the key at the driver's door handle from
close range and press the %/& button. There is a fault with KEYLESS-GO.
X
Lock/unlock the vehicle using the remote control function of
the key. Point the tip of the key at the driver's door handle from
close range and press the %/& button.
X Have KEYLESS-GO checked at a qualified specialist workshop.
If this does not work:
X Check the key battery (Y page 79) and replace it if necessary
(Y page 79).
X Lock (Y page 84) or unlock (Y page 84) the vehicle using
the emergency key element. You have lost a key. X
Have the key deactivated at a qualified specialist workshop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. Key
81Opening and closing Z

Problem Possible causes/consequences and
M Solutions
You have lost the emer-
gency key element. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. 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 330).
or
X Jump-start the vehicle (Y page 331).
or
X Consult a qualified specialist workshop. Only vehicles without a
DIRECT SELECT lever:
The engine cannot be
started using the key. The steering lock is mechanically blocked.
X
Remove the key and reinsert it into the ignition lock. While doing
this, turn the steering wheel in both directions. The engine cannot be
started using KEYLESS-
GO. The key is in the
vehicle. Ad
oor is open. Therefore, the key cannot be detected as easily.
X Close the door and try to start the vehicle again. There is interference from a powerful source of radio waves.
X
Start your vehicle with the key in the ignition lock. Doors
Important safety notes
G
WARNING
Only for the United Kingdom: if the vehicle
has been locked with the key or with KEY-
LESS-GO, the double lock function is activa-
ted as standard. It is then not possible to open
the doors from inside the vehicle.
Therefore, do not leave any people behind in
the vehicle, particularly children, elderly peo-
ple or people requiring special assistance. As
a result, they may not be able to free them-
selves in the event of an emergency. They
could be seriously or even fatally injured by
prolonged exposure to extremely high or low
temperatures, for example. In this case, res- cuing people from outside the vehicle is diffi-
cult.
Deactivate the interior motion sensor before
you lock the vehicle. The doors can then be
opened from the inside after the vehicle has
been locked from the outside.
G
WARNING
If children are left unsupervised in the vehicle,
they could:
R open a door from inside the vehicle at any
time, even if it has been locked
R start the vehicle using akey which has been
left in the vehicle
R release the parking brake 82
DoorsOpening and closing

i
If you activate the residual heat function
at high temperatures, only the ventilation
will be activated. The blower runs at
mediums peed.
X To deactivate: press theÌbutton.
The indicator lamp above the Ìbutton
goes out.
i It is possible that the residual heat func-
tion may be activated automatically an hour
after the key has been removed. The vehi-
cle is then ventilated for 30minutes to dry
the air-conditioning system.
Residual heat is deactivated automatically:
R after approximately 30 minutes
R when the ignition is switched on
R if the battery voltage drops Auxiliar
yheating
Important safety notes G
WARNING
Exhaust fumes are produced when the auxili-
ary heating is in operation. Inhaling these
exhaust fumes can be poisonous .You should
therefore switch off the auxiliary heating in
confined spaces without an extraction sys-
tem, e.g. a garage. G
WARNING
When operating the auxiliary heating parts of
the vehicle can get very hot. Make sure that
the exhaust system does not under any cir-
cumstances come into contact with easily
ignitable material such as dry grass or fuels.
The material could otherwise ignite and set
the vehicle alight. Choose your parking spot
accordingly.
Operating the auxiliary heating is thus pro-
hibited at filling stations or when your vehicle
is being refuelled. You must therefore switch
off the auxiliary heating at filling stations.
! Operating the auxiliary heating/ventila-
tion draws on the vehicle battery. After you have heated or ventilated the vehicle a
maximum of two times, drive for a longer
distance.
i Switch the auxiliary heating on regularly
once a month for about ten minutes.
The auxiliary heating heats the air in the
passenger compartment to the selected tem-
perature. It does not use the heat of the run-
ning engine to do this. The auxiliary heating
is operated directly using the vehicle's fuel.
For this reason, the tank content must be at
least at reserve fuel level to ensure that the
auxiliary heating functions.
The auxiliary heating/ventilation automati-
cally adjusts to changes in temperature and
weather conditions. For this reason, the aux-
iliary heating could switch from ventilation
mode to heating mode or from heating mode
to ventilation mode.
The auxiliary heating switches off automati-
cally after 50 minutes. This time limit can be
altered. To do this, visit a qualified specialist
workshop.
You cannot use the auxiliary ventilation to
cool the vehicle interior to a temperature
lower than the outside temperature.
Before switching on X
Turn the key to position 2in the ignition
lock.
X Set the temperature.
The auxiliary heating/ventilation can be acti-
vated even when climate control is set to
manual. Optimum comfort can be attained
when the system is set to automatic mode.
Set the temperature to 22 †.
The auxiliary heating/ventilation can be acti-
vated or deactivated using the remote control
or the button on the centre console.
The on-board computer can be used to spec-
ify up to three departure times, one of which
may be preselected (Y page 246). Operating the climate control system
149Climate control Z