Page 94 of 491

93 Safety and Security
Driving safety systems
The SBC brake system is automatically
activated when you:
unlock the vehicle with the SmartKey
or the KEYLESS-GO*
open the driver’s or passenger door
turn the SmartKey in the starter switch
to position1
in vehicles with KEYLESS-GO*, press
the start/stop button on gear selector
lever once
depress the brake pedal
release the parking brake
Warning!
G
The SBC 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. In such a case, the
red brake warning lamp (
page 354) and
warning messages in the instrument cluster
(
page 362) come on while driving. To
brake, the driver must then apply signifi-
cantly greater brake pedal pressure and de-
press the pedal much further to obtain the
expected braking effect. If necessary, apply
full pressure to the brake pedal. Brakes may
only be applied to the front wheels. Stop-
ping distance is increased!
If there is a malfunction in the SBC brake
system, we recommend that the vehicle be
transported with all wheels off the ground
using flatbed or appropriate wheel lift/dolly
equipment. A tow bar must be used if cir-
cumstances do not permit the use of the
recommended towing methods and the ve-
hicle requires towing with all four wheels on
the ground. Towing the vehicle with all four
wheels on the ground is only permissible for
distances up to 30 miles (50 km) and at a
speed not to exceed 30 mph (50 km/h). For
more information, refer to “Towing the vehi-
cle” (
page 430).
Page 287 of 491

286 OperationDriving instructionsPower assistance
Brakes
Warning!
G
The brake system requires electrical energy
for operation.
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. In such a case, the
red brake warning lamp (
page 354) and
warning messages in the instrument cluster
(
page 362) come on while driving. To
brake, the driver must then apply signifi-
cantly greater brake pedal pressure and de-
press the pedal much further to obtain the
expected braking effect. If necessary, apply
full pressure to the brake pedal. Brakes may
only be applied to the front wheels. Stop-
ping distance is increased!
If there is a malfunction in the SBC brake
system, we recommend that the vehicle be
transported with all wheels off the ground
using flatbed or appropriate wheel lift/dolly
equipment. A tow bar must be used if cir-
cumstances do not permit the use of the
recommended towing methods and the ve-
hicle requires towing with all four wheels on
the ground. Towing the vehicle with all four
wheels on the ground is only permissible for
distances up to 30 miles (50 km) and at a
speed not to exceed 30 mph (50 km/h). For
more information, refer to “Towing the vehi-
cle” (
page 430). For more information,
see “SBC brake system” (
page 92).
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.
Warning!
G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking ef-
fect. Maintain a safe distance from vehicles
in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an acci-
dent.
Page 378 of 491

377 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
(USA only);(Canada only)3
Brake fluid
Visit workshop
There is insufficient brake fluid in the
reservoir.
Risk of accident! Stop the vehicle and
notify an authorized Mercedes-Benz
Center. Do not add brake fluid! This
will not solve the problem.
Warning!
G
Driving while these messages are displayed
can result in an accident. Have your brake
system checked immediately.
If there is a malfunction in the SBC brake
system, we recommend that the vehicle be
transported with all wheels off the ground
using flatbed or appropriate wheel lift / dolly
equipment.
A tow bar must be used if circumstances do
not permit the use of the recommended
towing methods and the vehicle requires
towing with all four wheels on the ground.
Towing the vehicle with all four wheels on
the ground is only permissible for distances
u p t o 3 0 m i l e s ( 5 0 k m ) a n d a t a s p e e d n o t t o
exceed 30 mph (50 km / h). For more infor-
mation, refer to “Towing the vehicle”
(page 430).
If the SBC brake system enters its emergen-
cy operation mode, the driver must apply
significantly greater brake pedal pressure
and depress the pedal much further than
normal to obtain braking effect. If neces-
sary, apply full pressure to the brake pedal.
Brakes may only be applied to the front
wheels. Stopping distance is increased!
Do not add brake fluid before checking the
brake system. Overfilling the brake fluid res-
ervoir can result in spilling brake fluid on hot
engine parts and the brake fluid catching
fire. You can be seriously burned.!If you find that the brake fluid in the
brake fluid reservoir has fallen to the
minimum mark or below, have the
brake system checked for brake pad
thickness and leaks.
Page 432 of 491

431 Practical hints
Towing the vehicle
!
To be certain to avoid a possibility of
damage to the drive train, however, we
recommend the drive shaft be discon-
nected at the rear axle drive flange (ve-
hicles with 4MATIC: disconnected at
the front and rear axle drive flanges) 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 SBC 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.
Prior to towing the vehicle with all wheels on
the ground, make sure the SmartKey is in
starter switch position2.
If the SmartKey is left in the 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.
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 may only be applied to
the front wheels. Stopping distance is in-
creased! Adapt your driving style according-
ly. For more information, refer to “SBC brake
system” (
page 92).
With the engine not running, there is no
power assistance for the steering system. In
this case, it is important to keep in mind that
a considerably higher degree of effort is nec-
essary to steer the vehicle. Adapt your driv-
ing accordingly.