brake MERCEDES-BENZ R320 2008 W251 User Guide

57 Getting started
Driving
After a cold start, the automatic transmis-
sion shifts at a higher engine revolution.
This allows the catalytic converter
(gasoline engine) or the oxidation catalyst
(diesel engine) to reach its operating tem-
perature earlier.For more information, see
“Driving instructions” (
page 339).
!If you hear a warning signal and the
message
Release Parking Brake appears in
the multifunction display when driving off, you
have forgotten to release the parking brake.
Release the parking brake (
page 56).
iOnce the vehicle is in motion, the automatic
central locking system engages and the locking
knobs drop down.
The automatic door lock feature can be
deactivated (
page 183).
You can open a locked door from the inside.
Open door only when conditions are safe to
do so.
Warning!G
On slippery road surfaces, never downshift
in order to obtain braking action. This could
result in drive wheel slip and reduced vehi-
cle control. Your vehicle’s ABS will not pre-
vent this type of loss of control.
Warning!G
It is dangerous to shift the gear selector
lever out ofP orN if the engine speed is
higher than idle speed. If your foot is not
firmly on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
!Shift the automatic transmission to
positionP orR only when the vehicle is stopped
in order to avoid damaging the transmission.
!Do not run cold engine at high engine
speeds. Running a cold engine at high engine
speeds may shorten the service life of the
engine.
!Simultaneously depressing the accelerator
pedal and applying the brakes reduces engine
performance and causes premature brake and
drivetrain wear.

64 Getting started
Parking and locking
You have now completed your first drive.
You have properly stopped and parked
your vehicle. End your drive as follows.
Warning!G
With the engine not running, there is no
power assistance for the brake and the
steering system. In this case, it is important
to keep in mind that a considerably higher
degree of effort is necessary to brake and
steer the vehicle.
Warning!G
Do not park this vehicle in areas where com-
bustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
To reduce the risk of personal injury as a
result of vehicle movement, before turning
off the engine and leaving the vehicle
always:

Keep right foot on brake pedal.

Firmly depress parking brake pedal.

Shift the automatic transmission to
positionP.

Slowly release brake pedal.

When parked on an incline, turn front
wheel towards the road curb.

Turn the SmartKey in the starter switch
to position0 and remove the SmartKey
from the starter switch, or press the
start/stop button (vehicles with
KEYLESS-GO*).

Take the SmartKey or the SmartKey with
KEYLESS-GO* and lock vehicle when
leaving.

65 Getting started
Parking and locking
Parking brake
1Parking brake pedal
Step firmly on parking brake pedal1.When the engine is running, the warn-
ing lamp; (USA only) or3
(Canada only) in the instrument cluster
comes on.
Switching off headlamps
Turn the exterior lamp switch toM.
For more information, see “Lighting”
(
page 143).
Warning!G
Engaging the parking brake while the vehicle
is in motion can cause the rear wheels to
lock up. You could lose control of the vehicle
and cause an accident. In addition, the
vehicle’s brake lights do not light up when
the parking brake is engaged.Warning!G
When leaving the vehicle, always remove the
SmartKey or SmartKey with KEYLESS-GO*
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. Children could
release the parking brake and/or shift the
automatic transmission out of positionP,
either of which could result in an accident
and/or serious personal injury.
Warning!G
Getting out of your vehicle with the auto-
matic transmission not fully engaged in
positionP is dangerous. Also, when parked
on an incline, positionP alone may not
prevent your vehicle from moving, possibly
hitting people or objects.
Always set the parking brake in addition to
shifting to positionP (
page 192).
When parked on an incline, also turn front
wheel towards the road curb.

66 Getting started
Parking and locking
Turning off the engine
Shift the automatic transmission to
positionP (
page 192).
Apply the parking brake (page 65).Turning off with the SmartKey
Turn the SmartKey in the starter switch
to position0 (
page 40).
Remove the SmartKey from the starter
switch.
The immobilizer is activated.Turning off with KEYLESS-GO*
Press the KEYLESS-GO start/stop
button (
page 41) to turn off the
engine.
With the driver’s door closed, the
starter switch is now in position1. With
the driver’s door opened, the starter
switch is set to position0, same as
SmartKey removed from starter switch
(
page 39).
iIf the engine cannot be turned off as
described, see “Emergency engine shut-down”
(
page 520).
Warning!G
Do not turn off the engine before the vehicle
has come to a complete stop. With the
engine not running, there is no power assis-
tance 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 vehicle.
iAlways set the parking brake in addition to
shifting to positionP (
page 192).
When parked on an incline, also turn front wheel
towards the road curb.
!Observe instructions when taking the
vehicle through an automatic conveyor type
car wash (
page 406).
!If you turn off the engine using the
SmartKey and

remove the SmartKey from the starter
switch
or

open a front door
the automatic transmission will shift to park
positionP automatically.
Keep in mind that turning off the engine with the
SmartKey alone only will automatically shift the
automatic transmission to neutral positionN.
iIn an emergency you can turn off the engine
while driving by pressing and holding the
KEYLESS-GO start/stop button for
approximately 3 seconds.
!If you turn off the engine using the
KEYLESS-GO start/stop button and open a front
door, the automatic transmission will shift to
park positionP automatically.
Keep in mind that turning off the engine using
the KEYLESS-GO start/stop button alone only
will automatically shift the automatic transmis-
sion to neutral positionN.

99 Safety and Security
Driving safety systems
Driving safety systems
In this section you will find information on
the following driving safety systems:

ABS (Antilock Brake System)

BAS (Brake Assist System)

ESP® (Electronic Stability Program)

EBP (Electronic Brake Proportioning)
ABS
The Antilock Brake System (ABS) regulates
the brake pressure so that the wheels do
not lock during braking. This allows you to
maintain the ability to steer your vehicle.
The ABS is functional above a speed of
approximately 5 mph (8 km/h) indepen-
dent of road surface conditions.
On slippery road surfaces, the ABS will
respond even to light brake pressure.
The -indicator lamp in the instrument
cluster (
page 26) comes on when you
switch on the ignition. It goes out when the
engine is running.
Warning!G
The following factors increase the risk of
accidents:

Excessive speed, especially in turns

Wet and slippery road surfaces

Following another vehicle too closely
The driving systems described in this sec-
tion cannot reduce these risks or prevent
the natural laws of physics from acting on
the vehicle.
Always adjust your driving style to the
prevailing road and weather conditions and
keep a safe distance to other road users and
objects on the street.
iIn winter operation, the maximum effective-
ness driving systems described in this section is
only achieved with winter tires (
page 398) or
snow chains as required.
Warning!G
Do not pump the brake pedal. Use firm,
steady brake pedal pressure instead. Pump-
ing the brake pedal defeats the purpose of
the ABS and significantly reduces braking
effectiveness.

100 Safety and Security
Driving safety systems
Braking
At the instant one of the wheels is about to
lock up, a slight pulsation can be felt in the
brake pedal, indicating that the ABS is in
the regulating mode.
Keep firm and steady pressure on the
brake pedal while experiencing the pul-
sation.
Continuous, steady brake pedal pressure
yields the advantages provided by the ABS,
namely braking power and ability to steer
the vehicle.
The pulsating brake pedal can be an
indication of hazardous road conditions
and functions as a reminder to take extra
care while driving.Emergency brake maneuver
Keep continuous full pressure on the
brake pedal.
For more information, see the “Practical
Hints” section (
page 414).
Warning!G
When the ABS is malfunctioning, the BAS,
the ESP®, and the Electronic Traction
System are also switched off. The basic
driving and braking functions are still avail-
able.
When the ABS is malfunctioning, the wheels
may lock during hard braking, reducing
steering capability and extending the brak-
ing distance.
Warning!G
The ABS cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase braking or steering efficiency be-
yond that afforded by the condition of the
vehicle brakes and tires or the traction
afforded. The ABS cannot prevent acci-
dents, including those resulting from exces-
sive speed in turns, following another
vehicle too closely, or hydroplaning. Only a
safe, attentive, and skillful driver can pre-
vent accidents. The capabilities of an ABS
equipped vehicle must never be exploited in
a reckless or dangerous manner which
could jeopardize the user’s safety or the
safety of others.

101 Safety and Security
Driving safety systems
BAS
The Brake Assist System (BAS) operates in
emergency situations. If you apply the
brakes very quickly, the BAS automatically
provides full brake boost, thereby poten-
tially reducing braking distance.
Apply continuous full braking pressure
until the emergency braking situation is
over.
The ABS will prevent the wheels from
locking.
When you release the brake pedal, the
brakes function again as normal. The BAS
is then deactivated.
ESP®
The Electronic Stability Program (ESP®) is
operational as soon as the engine is run-
ning and monitors the vehicle’s traction
(force of adhesive friction between the
tires and the road surface) and handling.
The ESP
® recognizes when a wheel is
spinning or if the vehicle starts to skid. By
applying brakes to the appropriate wheel
and by limiting engine output, the ESP
®
helps stabilize the vehicle. The ESP® is
especially useful while driving off and on
wet or slippery road surfaces. The ESP
®
also stabilizes the vehicle during braking
and steering maneuvers.
The ESP
® warning lampv in the instru-
ment cluster (
page 26) flashes when the
ESP® is engaged.
The ESP
® warning lampv in the instru-
ment cluster comes on when you switch on
the ignition. It goes out when the engine is
running.
Warning!G
If the BAS is malfunctioning, the brake sys-
tem is still functioning, but without the addi-
tional brake boost available that BAS would
normally provide in an emergency braking
maneuver. Therefore, the braking distance
may increase.
Warning!G
The BAS cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase braking efficiency beyond that
afforded by the condition of the vehicle
brakes and tires or the traction afforded.
The BAS cannot prevent accidents, includ-
ing those resulting from excessive speed in
turns, following another vehicle too closely,
or hydroplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The
capabilities of a BAS equipped vehicle must
never be exploited in a reckless or danger-
ous manner which could jeopardize the
user’s safety or the safety of others.

102 Safety and Security
Driving safety systems
Warning!G
Never switch off the ESP® when you see the
ESP® warning lampv flashing in the in-
strument cluster. In this case, proceed as
follows:

While driving off, apply as little throttle
as possible.

While driving, ease up on the accelera-
tor.

Adapt your speed and driving style to
the prevailing road conditions.
Failure to observe these guidelines could
cause the vehicle to skid.
The ESP
® cannot prevent accidents result-
ing from excessive speed.
Warning!G
The ESP® cannot prevent the natural laws of
physics from acting on the vehicle, nor can
it increase the traction afforded. The ESP
®
cannot prevent accidents, including those
resulting from excessive speed in turns, fol-
lowing another vehicle too closely, or hydro-
planing. Only a safe, attentive, and skillful
driver can prevent accidents. The capabili-
t i e s o f a n E S P
® equipped vehicle must never
be exploited in a reckless or dangerous
manner which could jeopardize the user’s
safety or the safety of others.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO* start/stop button in
position0or1) when the vehicle is being towed
with one axle raised.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty
!Vehicles with 4MATIC must not be towed
with one axle raised.
!Vehicles with 4MATIC:
Operational or performance test must only be
conducted on a two-axle dynamometer. If such
tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.

103 Safety and Security
Driving safety systems
For more information, see the “Practical
hints” section (
page 419) and
(
page 435).ETS/4-ETS (Electronic Traction System)
The Electronic Traction System is part of
the ESP
®.
The Electronic Traction System improves
the vehicle’s ability to utilize available trac-
tion, especially under slippery road condi-
tions. The brakes are applied to the
spinning wheel and power is transferred to
the wheel(s) with traction.
When you switch off the ESP
®, the
Electronic Traction System is still operat-
ing and will still apply the brake to a
spinning wheel.
For more information, see the “Practical
hints” section (
page 414) and
(
page 427).
!Vehicles with 4MATIC:
Because the ESP® operates automatically, the
engine and ignition must be shut off (SmartKey
in starter switch position0 or1 or KEYLESS-GO*
start/stop button in position0or1) when test-
ing the parking brake on a brake test dynamom-
eter and such testing should be no longer than
10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
iThe ESP® will only function properly if you
use wheels of the recommended tire size
(
page 529).
Warning!G
The Electronic Traction System cannot
prevent the natural laws of physics from act-
ing on the vehicle, nor can it increase the
traction afforded. The Electronic Traction
System cannot prevent accidents, including
those resulting from excessive speed in
turns, following another vehicle too closely,
or hydroplaning. Only a safe, attentive, and
skillful driver can prevent accidents.
The capabilities of an Electronic Traction
System equipped vehicle must never be
exploited in a reckless or dangerous manner
which could jeopardize the user’s safety or
the safety of others.
iIf the yellow ESP® warning lampv
comes on while driving, the Electronic Traction
System is being switched off temporarily to
prevent overheating of the drive wheel brakes.
In addition, the message
ESP Unavailable
See Operator’s Manual
appears in the
multifunction display.

104 Safety and Security
Driving safety systems
Switching off the ESP®
To improve the vehicle’s traction, switch
off the ESP® in driving situations where it
would be advantageous to have the drive
wheels spin and thus cut into surfaces for
better grip such as:

when driving with snow chains

in deep snow

in sand or gravelWhen you switch off the ESP
®

the ESP® does not stabilize the vehicle

the engine output is not limited, which
allows the drive wheels to spin and
thus cut into surfaces for better grip

the Electronic Traction System will still
apply the brake to a spinning wheel

the ESP® continues to operate when
you are braking

you cannot activate the cruise control
or the Distronic* system

the cruise control or the Distronic*
system switch off if currently activatedThe ESP
® switch is located on the upper
part of the center console.
1ESP
® switch
With the engine running, press ESP®
switch1.
The ESP
®warning lampv in the in-
strument cluster comes on.
The ESP
® is deactivated.
Warning!G
The ESP® should not be switched off during
normal driving other than in the circum-
stances described below. Disabling of the
system will reduce vehicle stability in stan-
dard driving maneuvers.
Do not switch off the ESP
® when a spare
wheel is mounted.
Warning!G
Switch on the ESP® immediately if the afore-
mentioned circumstances do not apply any-
more. Otherwise the ESP
® will not stabilize
the vehicle when it is starting to skid or a
wheel is spinning.
iWhen the ESP® is switched off and one or
more drive wheels are spinning, the ESP® warn-
ing lamp v in the instrument cluster flashes.
However, the ESP
® will then not stabilize the
vehicle.