MERCEDES-BENZ R320 2008 W251 Repair Manual

60 Getting started
Driving
Switching on windshield wipers
Turn the combination switch to the
desired position depending on the
intensity of the rain.
MWindshield wipers off
USlow intermittent wiping
Rain sensor operation with low
sensitivity.
VFast intermittent wiping
Rain sensor operation with high
sensitivity.
uSlow continuous wiping
tFast continuous wipingIntermittent wiping
Only switch on intermittent wiping under
wet weather conditions or in the presence
of precipitation.
When you select intermittent wiping, the
rain sensor is activated. The rain sensor
automatically sets a suitable wiping
interval depending on the wetness of the
sensor surface.
Turn the combination switch to
positionU orV.
!Do not operate the windshield wipers when
the windshield is dry. Dust that accumulates on
a windshield might scratch the glass and/or
damage the wiper blades when wiping occurs on
a dry windshield. If it is necessary to operate the
windshield wipers in dry weather conditions,
always operate the windshield wipers with
windshield washer fluid (
page 61).
!If anything blocks the windshield wipers
(leaves, snow, etc.), switch them off
immediately.

For safety reasons, stop the vehicle in a safe
location and

remove the SmartKey from the starter
switch
or

turn off the engine by pressing the
KEYLESS-GO* start/stop button and
open the driver’s door (with the driver’s
door open, starter switch is in
position0, same as with SmartKey
removed from starter switch)
before attempting to remove any blockage.

Remove blockage.

Turn the windshield wipers on again.If the windshield wipers fail to function at all in
combination switch positionU orV,

set the combination switch to the next
higher wiper speed

have the windshield wipers checked at the
nearest authorized Mercedes-Benz Light
Truck Center
!Do not leave windshield wipers on an
intermittent setting when the vehicle is taken
to an automatic car wash or during windshield
cleaning. Windshield wipers will operate in the
presence of water sprayed on the windshield,
and windshield wipers may be damaged as a
result.
!If you have set intermittent wiping, dirt on
the surface of the rain sensor or optical effects
may cause the windshield wipers to wipe in an
undesired fashion. This could then damage the
windshield wiper blades or scratch the wind-
shield. You should therefore switch off the wind-
shield wipers when weather conditions are dry.

61 Getting started
Driving
After the initial wipe, pauses between
wipes are automatically controlled by the
rain sensor.
Single wipe
Press the combination switch briefly in
direction of arrow1 (
page 59) to
the resistance point.
The windshield wipers wipe one time
without washer fluid.Wiping with windshield washer fluid
Press the combination switch in
direction of arrow1 (
page 59) past
the resistance point.
The windshield wipers operate with
washer fluid.
For information on filling up the washer
reservoir, see “Windshield/rear window
washer system and headlamp cleaning
system*” (
page 362).
Rear window wiper/washer
The combination switch is located on the
left of the steering column.
Combination switch
1Rear window wiper switch
2Wiping rear window with washer fluid
3Intermittent wiping
4Rear window wiper off
5Wiping rear window with washer fluid
iIntermittent wiping is interrupted when the
vehicle is at a standstill and a front door is
opened. This protects persons getting into or out
of the vehicle from being sprayed.
Intermittent wiping will be continued when all
doors are closed and

the automatic transmission is set to
positionD or R
or

the wiper setting is changed using the
combination switch
iTo prevent smears on the windshield or
noisy/chattering wiper blades, wipe with wind-
shield washer fluid every now and then even
when it is raining.

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.

68 Getting started
Parking and locking
Exit the vehicle and close all doors and
the tailgate.
Locking with the SmartKey
Press button‹on the SmartKey
(
page 38).
With the tailgate and all doors closed,
the turn signal lamps flash three times.
The locking knobs on the doors move
down. The anti-theft alarm system is
armed.
For more information, see “Locking and
unlocking” (
page 110).Locking with KEYLESS-GO*
1Lock button on the outside door handle
Press lock button1 on an outside
door handle.
With the tailgate and all doors closed,
the turn signal lamps flash three times.
The locking knobs on the doors move
down. The anti-theft alarm system is
armed.
For more information, see “Locking and
unlocking” (
page 110).
iIf you hear a warning signal you have
forgotten to switch off the exterior lamps before
opening the driver’s door.
In addition the message
Switch Off Lights
appears in the multifunction display.
Switch off the headlamps.
!Failure to switch off the headlamps when
leaving the vehicle may result in a discharged
battery.

69 Safety and Security
Occupant safety
Panic alarm
Driving safety systems
Anti-theft systems