346 Practical hintsReplacing SmartKey batteriesIf the batteries in the SmartKey are dis-
charged, the vehicle can no longer be
locked or unlocked. It is recommended to
have the batteries replaced at an autho-
rized Mercedes-Benz Center.Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key out of the
SmartKey (
page 344).
Warning!
G
Batteries contain poisonous and corrosive
substances. Therefore keep the batteries
out of reach of children.
If a battery is swallowed, seek medical help
immediately.
iWhen inserting the batteries, make
sure they are clean and free of lint.iWhen replacing batteries, always re-
place both batteries. The required re-
placement batteries are available at
any Mercedes-Benz Center.
347 Practical hints
Replacing SmartKey batteries
1Mechanical key
2Unlocking the battery compartment
3Removing the battery compartment
4Slide
Insert mechanical key1in side
opening, push gray slide4 in direction
of arrow2.
The battery compartment is unlatched.
Pull battery compartment2 out of the
housing in direction of arrow3.5Battery
6Contact spring
Remove the discharged batteries.
Using a lint-free cloth, insert new
batteries5 under the contact
spring6 with the plus (+) side facing
up.
Return battery compartment into hous-
ing until it locks into place.
Slide mechanical key1 back into the
SmartKey.
Check the operation of the SmartKey.
357 Practical hints
Batteries
Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof batteries only to avoid the
risk of acid burns in the event of an
accident.
Warning!
G
The brake system requires electrical power
to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. The same applies if
battery is disconnected. To brake, the driver
must then apply significantly greater brake
pedal pressure and depress the pedal much
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the
brake pedal. Brakes are only applied to the
front wheels. Stopping distance is in-
creased! Adjust your driving style according-
ly. For more information, see
“Electrohydraulic brake system”
(page 84).
Warning!
G
With a disconnected battery
you will no longer be able to turn the
SmartKey in the starter switch
the gear selector lever will remain
locked in positionP
360 Practical hintsTowing the vehicleMercedes-Benz recommends that the vehi-
cle be transported with all wheels off the
ground using flatbed or appropriate wheel
lift/dolly equipment.
When circumstances do not permit the
recommended towing methods, the vehi-
cle may be towed with all wheels on the
ground or front wheels raised only so far as necessary to have the vehicle moved to a
safe location where the recommended
towing methods can be employed.
!Use flatbed or wheel lift/dolly equip-
ment with SmartKey in starter switch
turned to position0.
Do not tow with sling-type equipment.
Towing with sling-type equipment over
bumpy roads will damage radiator and
supports.
To prevent damage during transport,
do not tie down vehicle by its chassis or
suspension parts.
Switch off the tow-away alarm and the
automatic central locking.
!If the vehicle is towed with the front
axle raised, the engine must be shut off
(SmartKey in starter switch position0
or1). Otherwise the ESP
® will immedi-
ately be engaged and will apply the rear
wheel brakes.
When towing the vehicle with all wheels
on the ground, the gear selector lever
must be in positionN and the
SmartKey must be in starter switch
position2.
When towing the vehicle with all wheels
on the ground or the front axle raised,
the vehicle may be towed only for dis-
tances up to 30 miles (50 km) and at a
speed not to exceed 30 mph
(50 km/h).
!To be certain to avoid a possibility of
damage to the transmission, however,
we recommend the drive shaft be dis-
connected at the rear axle drive flange
for any towing beyond a short tow to a
nearby garage. Warning!
G
If circumstances require towing the vehicle
with all wheels on the ground, always tow
with a tow bar if:
the engine will not run
there is a malfunction in the electrohy-
draulic brake system
there is a malfunction in the power sup-
ply or in the vehicle’s electrical system
as that will be necessary to adequately con-
trol the towed vehicle.
361 Practical hints
Towing the vehicle
Prior to towing the vehicle with all wheels on
the ground, make certain that the SmartKey
is in starter switch position2.
If the SmartKey is left in starter switch
position0 for an extended period of time, it
can no longer be turned in the switch. In this
case, the steering is locked. To unlock, re-
move SmartKey from starter switch and re-
insert.iTo signal turns while being towed with
the hazard warning flasher in use, turn
SmartKey in starter switch to
position2 and activate the combina-
tion switch for the left or right turn sig-
nal in the usual manner – only the
selected turn signal will operate.
Upon canceling the turn signal, the haz-
ard warning flasher will operate again.
Warning!
G
The brake system requires electrical power
to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. To brake, the driver
must then apply significantly greater brake
pedal pressure and depress the pedal much
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the
brake pedal. Brakes are only applied to the
front wheels. Stopping distance is in-
creased! Adapt your driving style according-
ly. For more information, see
“Electrohydraulic brake system”
(page 84).
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the ve-
hicle. Adapt your driving accordingly.
!Towing of the vehicle should only be
done using the properly installed tow-
ing eye bolt. Never attach tow cable,
tow rope or tow rod to the vehicle chas-
sis, frame or suspension parts.iWhen towing the vehicle with all wheels
on the ground, please note the follow-
ing:
With the automatic central locking acti-
vated and the SmartKey in starter
switch position2 the vehicle doors
lock if the left front wheel as well as the
right rear wheel are turning at vehicle
speeds of approximately 9 mph
(15 km/h) or more.
To prevent the vehicle door locks from
locking, deactivate the automatic
central locking (
page 137).
362 Practical hintsTowing the vehicleInstalling/reinstalling towing eye bolt
Take the towing eye bolt1 from its
storage compartment (
page 342).1Towing eye bolt
Remove cover from the access hole.
Screw towing eye bolt1 in to its stop.
Remove the towing eye bolt when you
no longer need it. To do this, carry out
the above steps in reverse order.
Points to bear in mind
The vehicle must not be tow-started.
If the vehicle is to be towed, only tow it
with all wheels on the ground.
If the vehicle has suffered transmission
damage, only tow it with the propeller
shaft disconnected.
Before towing the vehicle, make sure
the battery is connected and charged.
Otherwise you will not be able to switch
on the ignition and move the selector
lever to N. There will then be no power
assistance when steering and braking.
Transporting the vehicle
The towing eye bolt can be used to pull the
vehicle onto a trailer or transporter for
transporting purposes.
Move the selector lever to N.
iThe gear selector lever will remain
locked in positionP and the SmartKey
will not turn in the starter switch if the
battery is disconnected or discharged.
See notes on the battery (
page 356).
!Only secure the tow bar to the towing
eye bolt. The vehicle could otherwise
be damaged.!Your vehicle is equipped with a front
towing eye bolt only (
page 362).
You cannot tow other vehicles with
your vehicle.
!Due to the low clearance height of the
SLR, care must be taken when loading
and unloading from a transporter to
avoid damaging the vehicle body work.
To secure the vehicle, only tie it down
by the wheels or tires. Otherwise it
could be damaged.
385 Technical terms
ABS
(A
nti-lock B
raking S
ystem)
Prevents the wheels from locking up
during braking so that the vehicle can
continue to be steered.
Accessory weight
(
page 281)
ACL
(Airbrake/C
entral L
ocking)
Controls the locking mechanism of the
Airbrake and the central locking sys-
tem.
Air pressure
(
page 281)
Aspect ratio
(page 281)BabySmart
TM airbag deactivation
system
This system detects if a special system
compatible child restraint seat is in-
stalled on the front passenger seat. The
system will automatically deactivate
the passenger front airbag when such a
seat is properly installed (PASSENGER
AIRBAG OFF indicator lamp on the low-
er center console illuminates and re-
mains illuminated).
BabySmartTM compatible child seats
Special restraint system for children.
The sensor system for the passenger
seat prevents deployment of the pas-
senger front airbag if a BabySmart
TM
compatible child seat is installed. See
an authorized Mercedes-Benz Center
for availability.
Bar
(
page 281)BAS
(B
rake As
sist S
ystem)
System for potentially reducing braking
distances in emergency braking situa-
tions. The system is activated when it
senses an emergency based on how
fast the brake is applied.
Bead
(
page 281)
Bi-Xenon headlamps
Headlamps which use an electric arc as
the light source and produce a more in-
tense light than filament headlamps.
Bi-Xenon headlamps produce low
beam and high beam.
CAC
(Customer A
ssistance C
enter)
Mercedes-Benz customer service cen-
ter, which can help you with any ques-
tions about your vehicle and provide
assistance in the event of a break-
down.
386 Technical termsCAN system
(C
ontroller A
rea N
etwork)
Data bus network serving to control ve-
hicle functions such as door locking or
windshield wiping depending on vehi-
cle settings and/or ambient condi-
tions.
Cockpit
All instruments, switches, buttons and
indicator/warning lamps in the passen-
ger compartment needed for vehicle
operation and monitoring.
Cold tire inflation pressure
(
page 281)
Control system
The control system is used to call up
vehicle information and to change
component settings. Information and
messages appear in the multifunction
display. The driver uses the buttons on
the multifunction steering wheel to
navigate through the system and to ad-
just settings.Cruise control
Driving convenience system for auto-
matically maintaining the vehicle speed
set by the driver.
Curb weight
(
page 281)
DOT
(Department o
f Transportation)
(
page 282)
Engine number
The number set by the manufacturer
and placed on the cylinder block to
uniquely identify each engine pro-
duced.
Engine oil viscosity
Measure of the internal oil friction (vis-
cosity) at different temperatures. The
higher the temperature the oil can tol-
erate without thinning too much, or the
lower the temperature it can tolerate
without thickening too much, the bet-
ter the viscosity characteristics of the
oil.ESP
®(Eectronic S
tability P
rogram)
Improves vehicle handling and direc-
tional stability.
ETD
(E
mergency T
ensioning D
evice)
Device which deploys in certain frontal
and rear collisions exceeding the sys-
tem's threshold to tighten the seat
belts.
->SRS
GAWR
(G
ross A
xle W
eight R
ating)
(
page 282)
Gear range
Number of gears which are available to
the automatic transmission for shifting.
The automatic gear shifting process
can be adapted to specific operating
conditions using the gear selector lever
or the steering wheel gearshift control
buttons.