2008 MERCEDES-BENZ C300 C S button

67 Safety and Security
Anti-theft systems
Arming: Lock the vehicle with the
SmartKey or KEYLESS-GO* (Canada
only).
The turn signal lamps flash three times,
and an acoustic signal sounds three
times, to indicate that the alarm sys-
tem is armed.
Indicator lamp1 begins to flash after
approximately 15 seconds after arming
the alarm system.
Disarming: Unlock your vehicle with
the SmartKey or KEYLESS-GO*
(Canada only).
The turn signal lamps flash once, and
an acoustic signal sounds once, to
indicate that the alarm system is
disarmed.
Canceling the alarm
To cancel the alarm, do one of the
following:
Insert the SmartKey or SmartKey with
KEYLESS-GO* (Canada only) in the
starter switch.
or
Press the Œ or ‹ button on the
SmartKey or SmartKey with
KEYLESS-GO* (Canada only).
In vehicles with KEYLESS-GO* (Canada
only):
Grasp an outside door handle.
The SmartKey with KEYLESS-GO
(Canada only) must be within 3 ft (1 m)
of the vehicle.
or
Press the KEYLESS-GO (Canada only)
start/stop button (
page 84).
The SmartKey with KEYLESS-GO
(Canada only) must be inside the vehi-
cle.
iIf the turn signal lamps do not flash three
times, and the acoustic signal does not sound
three times, one of the following elements may
not be properly closed:

a door

the trunk
the alarm system is armed.
With a door open, close the door and lock the ve-
hicle again. The turn signal lamps flash three
times, and an acoustic signal sounds three
times, to indicate that the alarm system is armed
and the vehicle is locked. If you open the un-
locked door again the alarm system will be trig-
gered.With the trunk open, close the trunk lid. The ve-
hicle will lock and the turn signal lamps flash
three times, and an acoustic signal sounds three
times, to indicate that the alarm system is armed
and the vehicle is locked.
iThe vehicle will lock and the alarm system
will rearm automatically after approximately 40
seconds if neither a door nor the trunk lid was
opened.

70 Controls in detail
Locking and unlocking
SmartKey
Your vehicle comes supplied with two
SmartKeys, each with remote control and
a removable mechanical key.
The SmartKey provides an extended oper-
ating range. To prevent theft, however, it is
advisable to only unlock the vehicle when
you are in close proximity to it.
The SmartKey centrally locks and unlocks,
when set to factory settings (
page 71):

the doors

the trunk

the fuel filler flap
SmartKey with remote control
1‹ Lock button
2ŠOpening button for trunk
(
page 269)
3Mechanical key locking tab
4ŒUnlock button
5Battery check lamp
6ÂPanic button (
page 58)
!To prevent possible malfunction, avoid ex-
posing the SmartKey to high levels of electro-
magnetic radiation.
Warning!G
When leaving the vehicle, always remove the
SmartKey from the starter switch, take it
with you, and lock the vehicle. Do not leave
children unattended in the vehicle, or with
access to an unlocked vehicle. A child’s
unsupervised access to a vehicle could
result in an accident and/or serious person-
al injury.
Warning!G
To prevent possible personal injury, always
keep hands and fingers away from the door
or trunk lid opening when closing a door or
the trunk. Be especially careful when small
children are around.
Before closing doors, make sure there is no
possibility of someone getting caught in a
door during closing.

71 Controls in detail
Locking and unlocking
Factory setting
Global unlocking: Press buttonŒ.

All turn signal lamps flash once.

An acoustic signal sounds once.

The locking knobs in the doors
move up.

The anti-theft alarm system is dis-
armed.

The locator lighting will also come
on if it is dark and the feature is ac-
tivated in the control system
(
page 172).
iUSA only:
This device complies with Part 15 of the FCC
Rules. Operation is subject to the following two
conditions:
(1) This device may not cause harmful interfer-
ence, and
(2) this device must accept any interference re-
ceived, including interference that may
cause undesired operation.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iCanada only:
This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference re-
ceived, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iYou can also open and close the door win-
dows and tilt/sliding sunroof, or the panorama
roof with power tilt/ sliding panel* using the
SmartKey (
page 123).
!If you cannot lock or unlock the vehicle with
the SmartKey, then either the batteries in the
SmartKey are discharged, the SmartKey is mal-
functioning or the vehicle batteries are drained.

Check the batteries in the SmartKey and re-
place them if necessary (
page 428).

Use the mechanical key to unlock the driv-
er’s door (
page 424) and trunk
(
page 425).

Use the mechanical key to lock and trunk
(
page 272).

Have the vehicle batteries and their connec-
tions checked (
page 446).
If the SmartKey is malfunctioning, contact
Roadside Assistance or an authorized
Mercedes-Benz Center.
iYour vehicle is equipped with an acoustic
lock and unlock confirmation signal feature. An
acoustic signal will sound when the vehicle is
locked or unlocked using the SmartKey.
If you wish to activate or deactivate the feature,
or adjust its signal volume, contact an authorized
Mercedes-Benz Center.

72 Controls in detail
Locking and unlocking
The vehicle will lock again automatically
and rearm the anti-theft alarm system
within approximately 40 seconds of un-
locking if:

neither a door nor the trunk is opened

the SmartKey is not inserted in the
starter switch

the central locking/unlocking switch is
not activated
Global locking: Press button‹.
With the trunk and doors closed:

All turn signal lamps flash three
times.

An acoustic signal sounds three
times.

The locking knobs in the doors
move down.

The anti-theft alarm system is
armed.Selective setting
If you frequently travel alone, you may wish
to reprogram the SmartKey so that press-
ing buttonŒ only unlocks the driver’s
door and the fuel filler flap.
Press and hold buttonsŒ and‹
simultaneously for about 6 seconds un-
til battery check lamp5 (
page 70)
flashes twice.
The SmartKey will then function as fol-
lows:
Unlocking driver’s door and fuel fill-
er flap: Press buttonΠonce.

All turn signal lamps flash once.

An acoustic signal sounds once.

The locking knob in the driver’s
door moves up.

The anti-theft alarm system is dis-
armed.

The locator lighting will also come
on if it is dark and the feature is ac-
tivated in the control system
(
page 172).
Global unlocking: Press buttonŒ
twice.

All turn signal lamps flash once.

An acoustic signal sounds once.

The locking knobs in the doors
move up.

The anti-theft alarm system is dis-
armed.

The locator lighting will also come
on if it is dark and the feature is ac-
tivated in the control system
(
page 172).

73 Controls in detail
Locking and unlocking
Global locking: Press button‹.
With the trunk and doors closed:

All turn signal lamps flash three
times.

An acoustic signal sounds three
times.

The locking knobs in the doors
move down.

The anti-theft alarm system is
armed.
Restoring to factory setting: Press
and hold buttonsŒ and‹ si-
multaneously for about 6 seconds until
battery check lamp5 (
page 70)
flashes twice.SmartKey with KEYLESS-GO*
(Canada only)
Vehicles equipped with KEYLESS-GO come
with two SmartKeys with KEYLESS-GO,
each with remote control and a removable
mechanical key.
The KEYLESS-GO function is integrated
into the SmartKey. On these vehicles, the
validity of the SmartKey with KEYLESS-GO
is checked every time you grasp an outside
door handle.
With the KEYLESS-GO function, you can
lock and unlock the vehicle without using
the remote control buttons on the
SmartKey and start the engine without in-
serting the SmartKey in the starter switch.
The SmartKey with KEYLESS-GO centrally
locks and unlocks, when set to factory set-
tings (
page 76):

the doors

the trunk

the fuel filler flap
SmartKey with KEYLESS-GO
1‹ Lock button
2ŠOpening button for trunk
(
page 269)
3Locking tab for mechanical key
4ΠUnlock button
5Battery check lamp
6ÂPanic button (
page 58)
iWhen any outside door handle other than
the driver’s outside door handle is grasped, the
vehicle is always centrally unlocked.
!To prevent possible malfunction, avoid ex-
posing the SmartKey with KEYLESS-GO to high
levels of electromagnetic radiation.

74 Controls in detail
Locking and unlocking
Warning!G
When leaving the vehicle, always take the
SmartKey with KEYLESS-GO* with you and
lock the vehicle. Do not leave children unat-
tended in the vehicle, or with access to an
unlocked vehicle. A child’s unsupervised ac-
cess to a vehicle could result in an accident
and/or serious personal injury.
They could start the vehicle with a valid
SmartKey with KEYLESS-GO left in the vehi-
cle or with the KEYLESS-GO button on the
starter switch, or they could release the
parking brake, thereby putting themselves
and others in danger. Switch off the engine
and take the SmartKey with KEYLESS-GO
with you even if you are only leaving the ve-
hicle for a short while.
Warning!G
To prevent possible personal injury, always
keep hands and fingers away from the door
or trunk lid opening when closing a door or
the trunk. Be especially careful when small
children are around.
Before closing doors, make sure there is no
possibility of someone getting caught in a
door during closing.
iUSA only:
This device complies with Part 15 of the FCC
Rules. Operation is subject to the following two
conditions:
(1) This device may not cause harmful interfer-
ence, and
(2) this device must accept any interference re-
ceived, including interference that may
cause undesired operation.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iCanada only:
This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference re-
ceived, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iYou can also open and close the door win-
dows and tilt/sliding sunroof, or the panorama
roof with power tilt/ sliding panel* using the
SmartKey with KEYLESS-GO (
page 123).
!If you cannot lock or unlock the vehicle with
the SmartKey with KEYLESS-GO, then either the
batteries in the SmartKey with KEYLESS-GO are
discharged, the SmartKey with KEYLESS-GO is
malfunctioning or the vehicle batteries are
drained.

Check the batteries in the SmartKey with
KEYLESS-GO and replace them if necessary
(
page 428).

75 Controls in detail
Locking and unlocking
Important notes on using KEYLESS-GO

You can also use the SmartKey with
KEYLESS-GO like a normal SmartKey
(
page 70).
The starter switch is under the
KEYLESS-GO button. Pull the
KEYLESS-GO button out in order to ac-
cess the starter switch.

You can combine KEYLESS-GO func-
tions with normal SmartKey functions
(e.g. unlocking with KEYLESS-GO and
locking with button ‹).

Always carry the SmartKey with
KEYLESS-GO with you.

Never store the SmartKey with
KEYLESS-GO together with:

Electronic items such as a tele-
phone or another SmartKey with
KEYLESS-GO

Metallic objects such as coins or
metal foil
Doing so could impair the function of
the KEYLESS-GO system.

To lock or unlock the vehicle, the
SmartKey with KEYLESS-GO must be
located outside the vehicle within ap-
proximately 3 ft (1 m) of a door or the
trunk lid.

If the vehicle has been parked for more
than 72 hours, you must pull an outside
door handle in order to activate the
KEYLESS-GO function.

In order to start the engine with the
SmartKey with KEYLESS-GO:

The SmartKey with KEYLESS-GO
must be located in the vehicle.

The KEYLESS-GO start/stop button
must be inserted in the starter
switch (
page 84).

The brake pedal must be firmly de-
pressed. Do not depress the accel-
erator.

If the SmartKey with KEYLESS-GO is
positioned farther away from the vehi-
cle, the system may no longer recog-
nize the SmartKey with KEYLESS-GO.
The vehicle then cannot be locked or
the engine started via the KEYLESS-GO
system.

If the SmartKey with KEYLESS-GO is re-
moved from the vehicle (e.g. if passen-
ger exits the vehicle with the SmartKey
with KEYLESS-GO)

when pressing the KEYLESS-GO
start/stop button or trying to lock
the vehicle with the outside door
handle the message
Key not rec-
ognized
appears in the multifunc-
tion display

Use the mechanical key to unlock the driv-
er’s door (
page 424) and trunk
(
page 425).

Use the mechanical key to lock and trunk
(
page 272).

Have the vehicle batteries and their connec-
tions checked (
page 446).
If the SmartKey with KEYLESS-GO is malfunc-
tioning, contact Roadside Assistance or an
authorized Mercedes-Benz Center.

76 Controls in detail
Locking and unlocking

with the engine running, the mes-
sage
Key not recognized appears
in the multifunction display while
driving off
Find the SmartKey with KEYLESS-GO or
change its present location immediate-
ly (e.g. place it on the front passenger
seat or insert it in shirt pocket).

If you have started the engine with the
KEYLESS-GO start/stop button, you
can turn it off again with:

the KEYLESS-GO start/stop button

the SmartKey with KEYLESS-GO in-
serted in the starter switch, when
the gear selector lever is in
positionP

Remember that the engine can be
started by anyone with a SmartKey
with KEYLESS-GO that is left inside the
vehicle.
Possibility 1: (One SmartKey with
KEYLESS-GO in the vehicle, one
SmartKey with KEYLESS-GO outside
the vehicle):
If you leave the SmartKey with
KEYLESS-GO behind when exiting and
locking the vehicle, no message
appears in the multifunction display.
Possibility 2: (One SmartKey with
KEYLESS-GO in the vehicle, no
SmartKey with KEYLESS-GO outside
the vehicle):
When exiting and trying to lock the ve-
hicle, the message
Key still in ve-
hicle
appears in the multifunction
display. The vehicle will not be locked.Factory setting
1Outside door handle
iYour vehicle is equipped with an acoustic
lock and unlock confirmation signal feature. An
acoustic signal will sound when the vehicle is
locked or unlocked using the SmartKey with
KEYLESS-GO.
If you wish to activate or deactivate the feature,
or adjust its signal volume, contact an authorized
Mercedes-Benz Center.