2004 MERCEDES-BENZ ML500 brakes

153 Controls in detail
Driving systems
Parktronic system* (Parking assist)
The Parktronic system assists the driver
during parking maneuvers. It visually and
audibly indicates the distance between the
vehicle and an obstacle.
With the ignition on, the Parktronic system
engages automatically at speeds up to ap-
proximately 10 mph (15 km / h) and deac-
tivates during higher speeds.Parktronic system monitors your vehicle’s
environment by means of six sensors in
the front bumper and four sensors in the
rear bumper.
1Sensors located in front bumperWarning!
G
Parktronic is a supplemental system. It is
not intended to nor does it replace the need
for extreme care. The responsibility during
parking and other critical maneuvers rests
always with the driver.
Make sure that no persons or animals are lo-
cated in the area in which your are maneu-
vering. They could otherwise be injured.
Special attention must be paid to objects
with smooth surfaces or low silhouettes
(e.g. trailer couplings, painted posts, or
street curbs). Such objects may not be de-
tected by the system and can damage the
vehicle.
The operational function of the Parktronic
system can be affected by dirty sensors, es-
pecially at times of snow and ice. For notes
on cleaning the Parktronic system sensors
(page 237).
Interference caused by other ultrasonic sig-
nals (e.g. working jackhammers or the air
brakes of trucks) can cause the system to
send erratic indications, and should be tak-
en into consideration.

154 Controls in detailDriving systemsMonitoring reach of sensors
The sensors must be free of dirt, ice and
snow or they will be unable to function
properly. Clean the sensors regularly with-
out scratching or damaging them.Front sensors
Rear sensorsMinimum distance
When an obstacle is located in this area, all
warning displays will light up and a warning
tone will sound. If the vehicle moves closer
than the minimum distance to an object,
the distance may no longer be displayed.
Center
approx. 39 in (100 cm)
Corners
approx. 24 in (60 cm)
Center
approx. 47 in (120 cm)
Corners
approx. 32 in (80 cm)
iDuring parking maneuvers, pay special
attention to objects located above or
below the height of the sensors (e.g.
planters or trailer hitches). The Parktro-
nic system will not detect such objects
at close range and damage to your ve-
hicle or the object may result.
Ultrasonic signals from outside sourc-
es (e.g. truck air brakes or jackham-
mers) may impair the operation of the
Parktronic system.
Center
approx. 8 in (20 cm)
Corners
approx. 6 in (15 cm)

194 OperationDriving instructionsBrakes
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.If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on and there is no audible warn-
ing (EBP), the brake fluid level in the
reservoir is too low.
Brake pad wear or a leak in the system may
be the reason for low brake fluid in the res-
ervoir.
Have the brake system inspected immedi-
ately. Contact your authorized
Mercedes-Benz Light Truck Center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact your authorized
Mercedes-Benz Light Truck Center.Warning!
G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking ef-
fect. Maintain a safe distance from vehicles
in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an acci-
dent.
!Be very careful not to endanger other
road users when you apply the brakes.
Refer to the description of the Brake
Assist System (BAS) (
page 78).

195 Operation
Driving instructions
Install only brake pads and brake fluid
recommended by Mercedes-Benz.
After hard braking, it is advisable to drive
on for some time, rather than immediately
parking, so the air stream will cool down
the brakes faster.
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine smoothly. Do not
place full load on the engine until the oper-
ating temperature has been reached.
When starting off on a slippery surface, do
not allow a drive wheel to spin for an ex-
tended period with the ESP switched off.
Doing so may cause serious damage to the
drivetrain which is not covered by the
Mercedes-Benz Limited Warranty.
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.

197 Operation
Driving instructions
The tread wear indicator appears as a solid
band across the tread.
Specified tire pressures must be main-
tained. This applies particularly if the tires
are subjected to high loads (e.g. high
speeds, heavy loads, high ambient temper-
atures).
Hydroplaning
Depending on the depth of the water on
the road, hydroplaning may occur even at
low speeds and with new tires. Reduce ve-
hicle speed, avoid track grooves in the
road and apply brakes cautiously in the
rain.Tire traction
The safe speed on a wet, snow covered or
icy road is always lower than on a dry road.You should pay particular attention to the
condition of the road whenever the outside
temperatures are close to the freezing
point.
Mercedes-Benz recommends M+S rated
radial-ply tires with a minimum tread depth
of approximately
1/6in (4 mm) on all four
wheels for the winter season to ensure
normal balanced handling characteristics.
On packed snow, they can reduce your
stopping distance as compared with sum-
mer tires.
Stopping distance, however, is still consid-
erably greater than when the road is not
covered with snow or ice. Exercise appro-
priate caution.
Warning!
G
Although the applicable federal motor vehi-
cle safety laws consider a tire to be worn
when the tread wear indicators (TWI) be-
come visible at approximately
1/16in
(1 .6 mm ), w e re c om men d th a t y o u do n o t a l-
low 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.
Warning!
G
If ice has formed on the road, tire traction
will be substantially reduced. Under such
weather conditions, drive, steer and brake
with extreme caution.

200 OperationDriving instructionsStanding water
Off-road driving
Read 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.
!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 water
into the engine and auxiliary equip-
ment, thus damaging them.
If you must drive through standing wa-
ter, drive slowly to prevent water from
entering the passenger compartment
or the engine compartment. Water in
these areas could cause damage to
electrical components or wiring of the
engine or transmission, or could result
in water being ingested by the engine
through the air intake, causing severe
internal engine damage. Any such dam-
age is not covered by the
Mercedes-Benz Limited Warranty.
Warning!
G
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 (dan-
ger of vehicle rollover). The vehicle might
otherwise rollover. If in doing so the vehicle
begins to show a tendency to roll, immedi-
ately 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.
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.

202 OperationDriving instructionsRims

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


Check if the vehicle jack 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.
Driving in steep terrain
Slope angle1 25°
226°

Switch to LOW RANGE mode before
starting to drive up or down steep in-
clines (
page 125).


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 60% grade.


Do not drive along the side of a slope
(danger of vehicle rollover). If in doing
so, the vehicle begins to show a ten-
dency to roll, immediately steer into a
line of gravity (straight up or downhill).


To help avoid the vehicle rolling over,
never turn it around on steep inclines.
If the vehicle cannot complete the at-
tempted climb, back it down in reverse
gear.


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


Check the brakes after a lengthy down-
grade drive.
Traction in steep terrain


Be easy on the accelerator and watch
for continuous wheel traction when
driving in steep terrain.
The 4-ETS helps greatly when starting
out on a steep incline when the front
wheels have then the tendency to slip
due to the weight shifting away the
front axle.iAvoid excessive engine speeds – drive
with moderate engine speeds
(max. 3000 RPM).
Select gear range2 or1 on the auto-
matic transmission (
page 121).

204 OperationDriving instructions

Switch off the exterior lamps as well as
the climate control.


Select gear range1 on the automatic
transmission (
page 121).


Enter the water only at a shallow spot,
driving at walking speed.


Do not stop vehicle while immersed in
water, and do not shut off the engine.
There is a very high level of driving re-
sistance in water. The surface is slip-
pery and may not be firm, making
pulling away in water difficult and dan-
gerous.


Clean mud off the tire tread after driv-
ing through water.


To dry the brakes, apply pressure to the
brake pedal several times after leaving
the water.
Crossing obstacles
!Never accelerate before driving into
the water. The bow wave could force
water into the engine and auxiliary
equipment, thus damaging them.
!Obstacles can damage the vehicle
undercarriage or suspension compo-
nents. If possible use the assistance of
a second person outside the vehicle to
scout the path you intend to take and
check for adequate ground clearance
when you cross obstacles with your ve-
hicle. The person assisting you outside
the vehicle should always be a safe dis-
tance away from the vehicle and posi-
tioned so that he or she cannot get hurt
in case of any unexpected vehicle
movement.
After off-road driving or crossing obsta-
cles, inspect vehicle for any damage,
especially vehicle undercarriage and
suspension components. Failure to do
so can adversely affect the vehicle's fu-
ture performance, including increased
chance of an accident.