warning MERCEDES-BENZ R320 2008 W251 Repair Manual

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.

105 Safety and Security
Driving safety systems
Switching on the ESP®
Press ESP® switch1.
The ESP
® warning lampv in the
instrument cluster goes out.
You are now again in normal driving
mode with the ESP
® switched on.
For more information, see the “Practical
hints” section (
page 414).
EBP
The EBP enhances braking effectiveness
by allowing the rear brakes to supply a
greater proportion of the braking effort
without a loss of vehicle stability.
For more information, see the “Practical
hints” section (
page 416) and
(
page 446).
Warning!G
When the ESP® warning lampv is
illuminated continuously, the ESP® is
switched off or is not operational due to a
malfunction.
Adapt your speed and driving to the prevail-
ing road conditions and to the non-operating
status of the ESP
®.
!Avoid spinning of a drive wheel for an
extended period of time with the ESP® switched
off. This may cause serious damage to the
drivetrain which is not covered by the
Mercedes-Benz Limited Warranty.
Warning!G
If the EBP is malfunctioning, the brake sys-
tem is still functioning. However, the rear
wheels may lock during hard braking, caus-
ing you to lose control over the vehicle and
possibly causing an accident. Adjust your
driving style to the non-operating status of
the EBP.

107 Safety and Security
Anti-theft systems
Arming the alarm system
The alarm system indicator lamp is located
to the lower left of the hazard warning
flasher.
1Alarm system indicator lamp
Lock the vehicle with the SmartKey or
with KEYLESS-GO* (
page 67).
The turn signal lamps flash three times
to indicate that the vehicle is locked.
Alarm system indicator lamp 1 starts
flashing.
Disarming the alarm system
Unlock the vehicle with the SmartKey
or with KEYLESS-GO* (
page 38).
The turn signal lamps flash once to
indicate that the vehicle is disarmed.
Alarm system indicator lamp 1 goes
out.Canceling the alarm
With the SmartKey
Insert the SmartKey in the starter
switch.
or
Press theŒ or ‹button on the
SmartKey.
With KEYLESS-GO*
Grasp an outside door handle.
The SmartKey with KEYLESS-GO must
be within 3 ft (1 m) of the vehicle.
or
Press the KEYLESS-GO start/stop
button (
page 41).
The SmartKey with KEYLESS-GO must
be inside the vehicle.
iIf the alarm stays on for more than
30 seconds, a call to the Response Center is
initiated automatically by the Tele Aid* system
(
page 322) provided that the Tele Aid* service
was subscribed to and properly activated, and
that necessary cellular service and GPS cover-
age are available.
iIf the turn signal lamps do not flash three
times, one of the following elements may not be
properly closed:

a door

the tailgate
Close the respective element and lock the
vehicle again.
iThe alarm system will rearm automatically
again after approximately 40 seconds if neither a
door nor the tailgate is opened.

111 Controls in detail
Locking and unlocking
Warning!G
When leaving the vehicle, always remove the
SmartKey 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. It is possible
for children to open a locked door from the
inside, which could result in an accident
and/or serious personal injury.
!To prevent possible malfunction, avoid ex-
posing the SmartKey to high levels of electro-
magnetic radiation.
iUSA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the following
two conditions:
(1) This device may not cause harmful
interference, and
(2) this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iCanada only:
This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iYou can also open and close

the door windows

the hinged quarter windows*

the tilt/sliding sunroof*

the tilt/sliding panel*
using the SmartKey, see “Summer opening
feature” (
page 244) and “Convenience clos-
ing feature” (
page 245).
!If you cannot lock or unlock the vehicle with
the SmartKey, the batteries in the SmartKey are
discharged, the SmartKey is malfunctioning, or
the vehicle battery is drained.

Check the batteries in the SmartKey and
replace them if necessary (
page 479).

Use the mechanical key to unlock the
driver’s door (
page 474).

Lock the vehicle as described in the
“Practical hints” section (
page 475).

Have the vehicle battery and the vehicle
battery connections checked (
page 503).
If the SmartKey is malfunctioning, contact
Roadside Assistance or an authorized
Mercedes-Benz Light Truck Center.

114 Controls in detail
Locking and unlocking
Warning!G
When leaving the vehicle, always take the
SmartKey with KEYLESS-GO* with you and
lock the vehicle. Do not leave children unat-
tended 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.
!To prevent possible malfunction, avoid
exposing the SmartKey with KEYLESS-GO to high
levels of electromagnetic radiation.
iUSA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the following
two conditions:
(1) This device may not cause harmful interfer-
ence, and
(2) this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iCanada only:
This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iYou can also open and close

the door windows

the hinged quarter windows*

the tilt/sliding sunroof*

the tilt/sliding panel*
using the SmartKey with KEYLESS-GO, see
“Summer opening feature” (
page 244) and
“Convenience closing feature” (
page 245).
!If you cannot lock or unlock the vehicle with
the SmartKey with KEYLESS-GO, the batteries in
the SmartKey with KEYLESS-GO are discharged,
the SmartKey with KEYLESS-GO is malfunction-
ing, or the vehicle battery is drained.

Check the batteries in the SmartKey with
KEYLESS-GO (
page 118) and replace
them if necessary (
page 479).

Use the mechanical key to unlock the
drivers’ door (
page 474).

Lock the vehicle as described in the
“Practical hints” section (
page 475).

Have the vehicle battery and the vehicle bat-
tery connections checked (
page 503).
If the SmartKey with KEYLESS-GO is malfunc-
tioning, contact Roadside Assistance or an
authorized Mercedes-Benz Light Truck Center.

119 Controls in detail
Locking and unlocking
Front doors
Pull on inside door handle2 on the
respective front door to open door.
If the door was locked, locking knob1
will move up.
Rear doors
Pull up locking knob1 on the respec-
tive rear door to unlock door.
Pull on inside door handle2 on the re-
spective rear door to open door.
Tailgate/Power tailgate*
A minimum height clearance of
7.2 ft (2.20 m) is required to open the
tailgate.iIf the vehicle has previously been locked
from the outside with the SmartKey or with
KEYLESS-GO*, opening a door from the inside
will trigger the anti-theft alarm system.
To cancel the alarm, do one of the following:
With the SmartKey

Insert the SmartKey in the starter switch.

Press theŒ or ‹button on the
SmartKey.
With KEYLESS-GO*

Grasp an outside door handle.

Press the KEYLESS-GO start/stop button
(
page 41).
The SmartKey with KEYLESS-GO must be
inside the vehicle.
Warning!G
Make sure the tailgate is closed when the
engine is running and while driving.
Among other dangers, deadly carbon
monoxide (CO) gases may enter vehicle
interior resulting in unconsciousness and
death.
!The tailgate swings open upwards automat-
ically. Always make sure there is sufficient over-
head clearance.

121 Controls in detail
Locking and unlocking
Closing the tailgate from the outside
manually
1Handle
Lower tailgate by pulling firmly on
handle1.
Close tailgate with hands placed flat
on it.
Once the tailgate touches the latch,
the tailgate will pull itself shut automat-
ically.Power tailgate*
In vehicles with power tailgate, you can

open and close the tailgate from the
inside and the outside electrically

limit the opening height of the tailgate

interrupt the opening/closing proce-
dure at any time by

pressing or pulling the
door-mounted remote tailgate
switch (
page 122)

pressing the Šbutton on the
SmartKey (
page 110) or
SmartKey with KEYLESS-GO*
(
page 113)

pressing the tailgate closing switch
(
page 124)

pressing the tailgate
closing/locking switch (vehicles
with KEYLESS-GO*) (
page 125)
Warning!G
To prevent possible personal injury, always
keep hands and fingers away from the cargo
compartment opening when closing the
tailgate. Be especially careful when small
children are around.
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. A child’s unsupervised
access to a vehicle could result in an
accident and/or serious personal injury.
iTo prevent an inadvertent lockout, do not
place the SmartKey in the cargo compartment.
Vehicles with KEYLESS-GO*: To prevent a
possible inadvertent lockout, the tailgate will
open automatically if a SmartKey with
KEYLESS-GO is recognized inside the vehicle.iIf the vehicle was previously centrally locked
with the SmartKey or KEYLESS-GO*, the tailgate
will lock automatically after closing it. The turn
signals flash three times to confirm locking.
!The tailgate swings open upwards automat-
ically. Always make sure there is sufficient over-
head clearance.

122 Controls in detail
Locking and unlocking
Opening the tailgate from the outside
You can unlock and open the tailgate
simultaneously from the outside when the
vehicle is at a standstill.
Press and hold buttonŠ on the
SmartKey or SmartKey with
KEYLESS-GO* until the tailgate unlocks
and opens.
While the tailgate is opening, an
acoustic signal sounds.
or
Vehicles with KEYLESS-GO*:
Pull on the handle (
page 120).
The tailgate is unlocked and opens.
While the tailgate is opening, an
acoustic signal sounds.Opening the tailgate from the inside
You can unlock and open the tailgate
simultaneously from the driver’s seat when
the vehicle is at a standstill.The switch is located on the door control
panel.
1Remote tailgate switchPull remote tailgate switch1 until
tailgate begins to open.
The tailgate opens. While the tailgate is
opening, an acoustic signal sounds.
Warning!G
Maintain sight of the area around the rear of
the vehicle while operating the tailgate with
the door-mounted remote tailgate switch or
with the Šbutton on the SmartKey or
SmartKey with KEYLESS-GO*. Monitor the
opening procedure carefully to make sure
no one is in danger of being injured.
To interrupt the opening procedure, press or
pull the door-mounted remote tailgate
switch or press the Šbutton on the
SmartKey or SmartKey with KEYLESS-GO*.