2007 MERCEDES-BENZ GL450 Vehicle level

325 Controls in detail
Useful features
Power outletsPower outlets are located

in the front center console
(
page 325)

in the front passenger footwell
(
page 325)

in the second-row footwell
(
page 326)

on the left-hand side of the cargo com-
partment (
page 326)
Power outlet in front center console
1Power outlet cover
Switch on the ignition (page 42).
Open cover plate (page 318).
Pull out cover1 and insert electrical
plug (cigarette lighter type).
Power outlet in front passenger
footwell
Switch on the ignition (page 42).
Flip up cover and insert electrical plug
(cigarette lighter type).
!If you use all power outlets in the vehicle,
make sure that the maximum current drawn
does not exceed 55 A.
iThe power outlets can be used to
accommodate 12V DC electrical accessories
(e.g. auxiliary lamps) up to a maximum of 240 W.
If the engine is off, the battery may become dis-
charged if used for long periods of time.
iYou can use the power outlets, except for
the power outlet in the front center console,
even if the ignition is switched off.
An emergency shut-off feature ensures that the
vehicle’s electrical voltage does not fall below a
minimum level. If the voltage drops to this mini-
mum level, the power outlets are automatically
switched off. This ensures that enough power re-
mains to start the engine.
iIf your vehicle is equipped with a smoking
package*, the storage compartment contains an
ashtray with cigarette lighter (
page 324) in-
stead.

351 Operation
Driving instructions
To help prevent brake disk corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes.
If your brake system is normally only sub-
jected to moderate loads, you should occa-
sionally test the effectiveness of the
brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.
Refer to the description of the Brake Assist
System (BAS) (
page 105).Brake pad wear or a leak in the system may
be the reason for low brake fluid in the
reservoir.
The brake fluid level in the reservoir may
be too low if the brake warning lamp in the
instrument cluster comes on and an
acoustic warning sounds although the
parking brake is released (
page 437).
Observe additional messages in the multi-
function display that may appear
(
page 472).
Have the brake system inspected
immediately. Contact an authorized
Mercedes-Benz Light Truck Center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Light Truck Center.
Only install brake pads and brake fluid
recommended by Mercedes-Benz.
After hard braking, it is advisable to drive
on for some time, rather than immediately
park, so that the air stream will cool down
the brakes faster.
Warning!G
Make sure not to endanger any other road
users when carrying out these braking
maneuvers.
Warning!G
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that
safe braking is substantially impaired. This
could result in an accident.
!When driving down long and steep grades,
relieve the load on the brakes by shifting into a
lower gear to use the engine’s braking power.
This helps prevent overheating of the brakes and
reduces brake pad wear.
When using the engine’s braking power, a drive
wheel may not spin for an extended period of
time, e.g. on slippery road surfaces. This may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited
Warranty.

353 Operation
Driving instructions
TiresTreadwear indicators (TWI) are required by
law. These indicators are located in six
places on the tread circumference and
become visible at a tread depth of
approximately
1/16in (1.6 mm), at which
point the tire is considered worn and
should be replaced.
The treadwear indicator appears as a solid
band across the tread.Specified tire inflation pressures must be
maintained. This applies particularly if the
tires are subjected to high loads (e.g. high
speeds, heavy loads, high ambient temper-
atures).
For more information, see “Tires and
wheels” (
page 385).

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

Take the SmartKey or the SmartKey with
KEYLESS-GO* with you and lock vehicle
when leaving.
Warning!G
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possi-
ble damage to your vehicle has occurred,
you should turn on the hazard warning flash-
ers, carefully slow down, and drive with cau-
tion to an area which is a safe distance from
the road.
Inspect the tires and the vehicle underbody
for possible damage. If the vehicle or tires
appear unsafe, have the vehicle towed to
the nearest Mercedes-Benz Light Truck
Center or tire dealer for repairs.
Warning!G
Although the applicable federal motor
vehicle safety laws consider a tire to be
worn when the treadwear indicators (TWI)
become visible at approximately
1/16in
(1.6 mm), we recommend that you do not
allow your tires to wear down to that level.
As tread depth approaches
1/8in (3 mm),
the adhesion properties on a wet road are
sharply reduced.
Depending upon the weather and/or road
surface (conditions), the tire traction varies
widely.
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle. Continued
driving with a flat tire or driving at high
speed with a flat tire will cause excessive
heat build-up and possibly a fire.

356 Operation
Driving instructions
If the vehicle is parked after being driven
on salt-treated roads, the braking efficien-
cy should be tested as soon as possible af-
ter driving is resumed.
For more information, see “Winter driving”
(
page 420).
Standing water
For more information, see “Driving through
water” (
page 362).
Warning!G
Make sure not to endanger any other road
users when carrying out these braking
maneuvers.
Warning!G
If the vehicle becomes stuck in snow, make
sure that snow is kept clear of the exhaust
pipe and from around the vehicle with the
engine running. Otherwise, deadly carbon
monoxide (CO) gases may enter vehicle in-
terior resulting in unconsciousness and
death.
To assure sufficient fresh air ventilation,
open a window slightly on the side of the ve-
hicle not facing the wind.
Warning!G
The outside temperature indicator is not de-
signed to serve as an ice-warning device and
is therefore unsuitable for that purpose. In-
dicated temperatures just above the freez-
ing point do not guarantee that the road
surface is free of ice.!Do not drive through flooded areas or water
of unknown depth. Before driving through water,
determine its depth. Never accelerate before
driving into water. The bow wave could force wa-
ter into the engine and auxiliary equipment, thus
damaging them.
If you must drive through standing water, drive
slowly to prevent water from entering the pas-
senger compartment or the engine compart-
ment.
Water in these areas could cause

damage to electrical components

wiring of the engine or transmission
or could result

in water being ingested by the engine
through the air intake, causing severe inter-
nal engine damage.
Any such damage is not covered by the
Mercedes-Benz Limited Warranty.
iSelect the raised level (page 281) before
driving through standing water.

357 Operation
Driving instructions
Off-road drivingRead this chapter carefully before you be-
gin off-road travel.
Familiarize yourself with the vehicle char-
acteristics and gear changing before you
attempt any difficult terrain off-road driv-
ing. We recommend that you start out with
easy off-road travel.
Warning!G
Do not load items on the basic cross bars*.
It may cause instability during some maneu-
vers which could result in an accident.
Drive slowly in unknown terrain. This will
make it easier to recognize unexpected ob-
stacles and avoid damage to the vehicle.
To help avoid the vehicle rolling over, never
turn it around on steep inclines. If the vehi-
cle cannot complete the attempted climb,
back it down in reverse gear.
Do not drive along the side of a slope. The
vehicle might otherwise rollover. If in doing
so the vehicle begins to show a tendency to
roll, immediately steer into a line of gravity
(straight up or downhill).
Never let the vehicle roll backwards in idle.
You may lose control of the vehicle if you
use only the service brake. For information
on driving downhill, see “Driving downhill”
(
page 361).
Warning!G
Sand, dirt, mud and other material having
friction property can cause exceptional wear
and tear as well as brake failure.
Have the brakes checked for dirt build-up
and cleaned. There is otherwise a risk that
full braking power may not be available in an
emergency.
Warning!G
Please be aware that by raising the vehicle
level, the center of gravity also rises. There-
fore, always ensure that the vehicle level is
as low as possible. With higher ride height
the ESP
® may activate earlier in certain
situations.

358 Operation
Driving instructions
Special driving features for off-road
driving
The following driving features are available
for specific kind of operation:

Off-road – ABS (page 104)

Off-road – ESP® (page 108)

Off-road – 4-ETS (page 110)

Hill start assist system (page 199)

LOW RANGE mode* (page 203)

Differential locks* (page 206)

Downhill Speed Regulation (DSR)
(
page 275)

Off-road driving program (Vehicles
without enhanced off-road package*)
(
page 279)

Air suspension (page 280)Off-road driving rules

Engage the off-road driving program
(
page 279) or LOW RANGE mode*
(
page 203) before driving under
off-road conditions.

If necessary, activate differential
locks* (
page 206).

Make sure you select a vehicle level
(
page 281) appropriate to the topo-
graphical conditions. Always make
sure the vehicle has enough ground
clearance.

Fasten items being carried as securely
as possible (
page 297).

Always navigate gradients with the en-
gine on and with the transmission en-
gaged in a gear. Switch on the DSR
(
page 276) to help maintain a preset
speed.
!Observe the following during off-road
driving:

Keep doors, tailgate, windows, and
tilt/sliding sunroof* closed whenever driving
off-road.

Adjust vehicle speed to condition of terrain.
The more uneven, rutty and steeper the ter-
rain, the lower the speed should be. Drive
through water slowly at an even speed,
avoiding a bow wave.

Be especially careful when driving in un-
known territory. It may be necessary to get
out of the vehicle and scout the path you in-
tend to take.

Watch out for obstacles, such as rocks,
holes, tree stumps and ruts.

Before driving through water, determine its
depth.

Do not stop vehicle while immersed in water,
and do not shut off the engine.

359 Operation
Driving instructions
Checklist before off-road driving
Engine oil level

Check the engine oil level with the oil
dipstick (
page 381).
Only with a proper oil level can the
vehicle obtain a trouble-free oil supply,
even on steep gradients.Tires

Check the tread depth and maintain
specified tire inflation pressure
(a placard with the recommended tire
inflation pressures is located on the
driver’s door B-pillar (
page 389)).

Check tires for possible damage and
remove foreign objects.

Replace missing valve caps.
Rims

Dented or bent rims can cause tire in-
flation pressure loss and damage the
tire beads. For this reason, check and,
if necessary, change rims before driv-
ing off-road.
Vehicle tool kit

Check if the vehicle jack (page 497)
is functional.

In all cases take the vehicle tool kit, a
strong tow rope, a shovel and a small
plank (to put under the vehicle jack on
sandy soil) with you.

In sandy soil, drive at a steady speed as al-
lowed by conditions. This helps overcome
the vehicle rolling resistance and reduces
the likelihood of the vehicle sinking into the
ground.

Do not initiate jumps with the vehicle. It
interrupts the forward momentum of the
vehicle.

Always drive onto slopes with the engine
running and the vehicle in gear.

Do not shift automatic transmission to
positionN.
Warning!G
Do not reduce the tire inflation pressure
before driving through sand. However, if you
do so, remember to correct the tire inflation
pressure (
page 396) before continuing
your trip. Driving with reduced tire inflation
pressure increases the risk of losing control
of the vehicle and rolling over.
!If the engine oil level warning lamp
(
page 476) comes on while driving, stop the
vehicle in a safe location or as soon at is safe to
do so. Check the engine oil level (
page 381).
The engine oil level warnings should not be
ignored. Extended driving with the symbol
displayed could result in serious engine damage
that is not covered by the Mercedes-Benz
Limited Warranty.

360 Operation
Driving instructions
Driving in steep terrain
Slope angle
1 Overhang angle, front
2Overhang angle, rear

Comply with the warnings
(
page 357) and rules for off-road
driving (
page 358).

Driving on embankments, slopes and
other steep inclines should only be
done straight up or downhill, i.e. in the
line of gravity. Maximum vehicle climb-
ing ability is a 100% grade which is
equivalent to a slope angle of
45 degrees. Keep in mind that the
climbing ability of the vehicle depends
on terrain conditions.

Shift automatic transmission to
position1 (
page 200).

Drive slowly.

Avoid excessive engine speeds – drive
with moderate engine speeds
(max. 3 000 rpm).

Utilize the engine’s braking power
when descending a slope, observe the
engine speed (do not overrev the en-
gine). Apply the service brake as need-
ed.

Check the brakes after a lengthy down-
grade drive.Vehicles with air
suspension pack-
age12
Raised level34°28°
Highway29°23°
Vehicles with
enhanced off-road
package*12
Off-road-level 336°30°
Off-road-level 234°28°
Off-road-level 131°25°
Highway29°23°
iFor maximum engine speed, see “Instru-
ment cluster” (
page 26) and see “Engine”
(
page 553).
Warning!G
Never turn the vehicle around on steep
inclines. The vehicle might roll over. If the
vehicle cannot complete the attempted
climb, back it down in reverse gear.