engine MERCEDES-BENZ R320 2008 W251 Owner's Guide

62 Getting started
Driving
6Rear window wiper indicator
Switch on the ignition (page 39).
Activating intermittent wipe
Turn rear window wiper switch 1 to
position3.
In the lower multifunction display you
will see indicator6, indicating that
the rear window wiper is activated.Deactivating intermittent wipe
Turn rear window wiper switch 1 to
position4 (
page 61).
Indicator6 for the rear window wiper
is cleared from the lower multifunction
display, indicating that the rear window
wiper is deactivated.
Wiping with windshield washer fluid
Turn and hold rear window wiper
switch 1 in position 2 or 5
(
page 61) until the rear window is
clean.
The rear window wiper operates with
washer fluid.
For information on filling up the washer
reservoir, see “Windshield/rear window
washer system and headlamp cleaning
system*” (
page 362).
Problems while driving
The engine runs erratically and misfires

An ignition cable may be damaged
(gasoline engine only).

The engine electronics may not be
operating properly.

Unburned gasoline may have entered
the catalytic converter and damaged it
(gasoline engine only).
Give very little gas.
Have the problem repaired by an
authorized Mercedes-Benz Light Truck
Center as soon as possible.
iThe rear window wiper engages auto-
matically when the automatic transmission is
shifted to positionR with the windshield wipers
switched on.

63 Getting started
Driving
The coolant temperature is above
248°F (120°C)
The coolant is too hot and is no longer
cooling the engine.
Stop the vehicle in a safe location as
soon as possible and turn off the
engine. Allow engine and coolant to
cool.
Check the coolant level and add
coolant if necessary (
page 360).In case of accident
If the vehicle is leaking fuel:
Do not start the engine under any
circumstances.
Notify local fire and/or police authori-
ties.
If the extent of the damage cannot be
determined:
Contact an authorized Mercedes-Benz
Light Truck Center or call Roadside
Assistance.
If no damage can be determined on the

major assemblies

fuel system

engine mount:
Start the engine in the usual manner.

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.

67 Getting started
Parking and locking
If you have started the engine with the
KEYLESS-GO start/stop button and
cannot turn it off as described above:
Remove the KEYLESS-GO start/stop
button from the starter switch.
Insert the SmartKey with KEYLESS-GO
into the starter switch.
The engine turns off. The starter switch
is in position0 (
page 40).
Releasing seat belts
Press the seat belt release button
(
page 51).
Allow the retractor to completely
rewind the seat belt by guiding the
latch plate.
Locking
!Make sure the seat belt retracts fully so that
the seat belt and/or latch plate cannot get
caught or pinched in the door or in the seat
mechanism. This can damage the seat belt and
impair the effectiveness of the seat belt, and/or
cause damage to the door and/or door trim
panel. Such damage is not covered by the
Mercedes-Benz Limited Warranty.
Damaged seat belts must be replaced.
Contact an authorized Mercedes-Benz Light
Truck Center.
Warning!G
To prevent possible personal injury, always
keep hands and fingers away from the door
openings when closing the doors.
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.
Warning!G
When leaving the vehicle, always remove the
SmartKey from the starter switch, take the
SmartKey with KEYLESS-GO* with you, and
lock your 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 personal injury.

70 Safety and Security
Occupant safety
In this section you will learn the most
important facts about the restraint
systems of the vehicle.
The restraint systems are

Seat belts (page 82)

Child restraints (page 92)

Lower Anchors and Tethers for
CH
ildren (LATCH) (page 91)
Additional protection provide

Supplemental Restraint System (SRS)
with

Air bags (page 72)

Air bag control unit (with crash
sensors)

Emergency Tensioning Device
(ETD) for seat belts (
page 85)

Active head restraints (page 86)Air bag system components with

Front passenger front air bag off
indicator lamp (
page 81)

Front passenger seat with Occupant
C
lassification System (OCS)
(
page 77)
Although independent systems, their
protective functions work in conjunction
with each other.The SRS system conducts a self-test when
the ignition is switched on and in regular
intervals while the engine is running. This
facilitates early detection of malfunctions.
The 1indicator lamp in the instrument
cluster (
page 26) comes on when the
ignition is switched on and goes out no
later than a few seconds after the engine
was started.
The SRS components are in operational
readiness if the 1indicator lamp is not
lit when the engine is running.
A malfunction in the system has been
detected if the 1indicator lamp:

fails to go out no later than approxi-
mately 4 seconds after the engine was
started

does not come on at all

comes on after the engine was started
or while driving
iFor information on infants and children
traveling with you in the vehicle and restraint
systems for infants and children, see “Children
in the vehicle” (
page 87).

78 Safety and Security
Occupant safety
Warning!G
If the 59indicator lamp illumi-
nates when an adult or someone larger than
a small individual is in the front passenger
seat, have the front passenger reposition
himself or herself in the seat until the
59 indicator lamp goes out, or
check whether objects are caught under or
around the seat.
More information about air bag display
messages (
page 438).
In the event of a collision, the air bag control
unit will not allow front passenger front air
bag deployment when the OCS classified
the front passenger seat occupant as being
up to or less than the weight of a typical
12-month-old child in a standard child re-
straint or if the front passenger seat is
sensed as being empty.
When the OCS senses that the front passen-
ger seat occupant is classified as being up
to or less than the weight of a typical
12-month-old child in a standard child
restraint, the 59indicator
lamp will illuminate when the engine is
started and remain illuminated, indicating
that the front passenger front air bag is de-
activated.
When the OCS senses that the front passen-
ger seat is classified as being empty, the
59indicator lamp will illumi-
nate when the engine is started and remain
illuminated, indicating that the front passen-
ger front air bag is deactivated.When the OCS senses that the front passen-
ger seat occupant is classified as being
heavier than the weight of a typical
12-month-old child seated in a standard
child restraint or as being a small individual
(such as a young teenager or a small adult),
the 59 indicator lamp will illu-
minate for approximately 6 seconds when
the engine is started and then, depending on
occupant weight sensor readings from the
seat, remain illuminated or go out. With the
59 indicator lamp illuminated,
the front passenger front air bag is deacti-
vated. With the 59indicator
lamp out, the front passenger front air bag is
activated.
When the OCS senses that the front passen-
ger seat occupant is classified as an adult or
someone larger than a small individual, the
59 indicator lamp will illumi-
nate for approximately 6 seconds when the
engine is started and then go out, indicating
that the front passenger front air bag is acti-
vated.

85 Safety and Security
Occupant safety
Enhanced seat belt reminder system
When the engine is started, the seat belt
telltale< will always illuminate
for 6 seconds to remind you and your
passengers to fasten your seat belts.
If the driver’s seat belt is not fastened
when the engine is started, an additional
warning chime will also sound for a maxi-
mum of 6 seconds or until the driver’s seat
belt is fastened.
If after these 6 seconds, the driver’s or the
front passenger’s seat belt (with the front
passenger seat occupied) are not fastened
with all doors closed,

the seat belt telltale< remains illu-
minated for as long as either the
driver’s or front passenger’s seat belt is
not fastened

and if the vehicle speed exceeds
15 mph (25 km/h), the seat belt
telltale< starts flashing and a
warning chime sounds with increasing
intensity for a maximum of 60 seconds
or until the driver’s and the front
passenger’s seat belt are fastened
If the driver’s or the front passenger’s
seat belt remains unfastened after
60 seconds, the warning chime stops
sounding and the seat belt
telltale< stops flashing but
continues to be illuminated.
The seat belt telltale< will only go out
if both the driver’s and the front passen-
ger’s seat belt (with the front passenger
seat occupied) are fastened, or the vehicle
is standing still and a front door is opened.
For more information, see “Practical hints”
(
page 420).Emergency Tensioning Device (ETD),
seat belt force limiter
The seat belts for following seats are
equipped with emergency tensioning de-
vices and seat belt force limiters:

front seats

outboard second-row seats

third-row seats
The ETD is designed to activate in the
following cases:

in frontal or rear-end impacts
exceeding the system deployment
threshold

in certain vehicle rollovers

if the restraint systems are operational
and functioning correctly, see
1indicator lamp (
page 424)
iThe ETDs for the front seats will only acti-
vate if the respective front seat belt is fastened
(latch plate properly inserted into buckle).
The ETDs for the rear seats will activate with or
without the respective seat belt fastened.

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.