2002 MERCEDES-BENZ ML320 brakes

217 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Brake assist system (BAS)The BAS is designed to maximize the vehicle’s braking
capability during emergency braking maneuvers by
having maximum power boost applied to the brakes
more quickly in emergency braking conditions than
might otherwise be afforded solely by the driver’s
braking style. This can help reduce braking distances
over what ordinary driving and braking style might do.
The BAS complements the antilock brake system (ABS).
Applying the brakes very quickly results in maximum
BAS assistance.
To receive the benefit of the system you must apply
continuous full braking power during the stopping
sequence. Do not reduce brake pedal pressure.
Once the brake pedal is released, the BAS is deactivated.
The malfunction indicator lamp for the electronic
stability program (ESP) is combined with the BAS
malfunction indicator lamp.
Wa r n i n g !
BAS cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase
braking efficiency beyond that afforded by the
condition of the vehicle brakes and tires or the
traction afforded. The BAS cannot prevent
accidents, including those resulting from excessive
speed in turns, following another vehicle too
closely, or aquaplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The
capabilities of a BAS equipped vehicle must never
be exploited in a reckless or dangerous manner
which could jeopardize the user’s safety or the
safety of others.

220 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
If the charging voltage falls below 10 volts, the
malfunction indicator lamp comes on and the ABS is
switched off. When the voltage is above this value again,
the malfunction indicator lamp should go out and the
ABS is operational.
If the ABS malfunction indicator lamp stays illuminated,
have the system checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.Notes:
To alert following vehicles to slippery road conditions
you discover, operate your hazard warning flashers as
appropriate.
Operating the vehicle on a single axle dynamometer
should only be done for briefly testing the brakes. To do
so, move selector lever to position “N”. The engine must
be shut off (key in steering lock position 0 or 1).
LOW RANGE – ABS
During off-road driving a special low range system for
the antilock brake system (ABS) is operational with
transmission in LOW RANGE mode, see page 229.
When applying the service brakes at speeds below
approximately 18 mph (30 km / h), the front wheels are
locked cyclically to shorten the braking distance (dig in
effect). This affects steering the vehicle.
Wa r n i n g !
ABS cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase
braking or steering efficiency beyond that afforded
by the condition of the vehicle brakes and tires or
the traction afforded. The ABS cannot prevent
accidents, including those resulting from excessive
speed in turns, following another vehicle too
closely, or aquaplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The
capabilities of an ABS equipped vehicle must never
be exploited in a reckless or dangerous manner
which could jeopardize the user’s safety or the
safety of others.

221 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Four-wheel electronic traction system (4-ETS+)
With the key in steering lock position 2, the yellow
4-ETS+ malfunction indicator lamp{ and the 4-ETS+
warning lampv come on and should go out when
the engine is running.
The 4-ETS+ improves vehicle’s ability to utilize available
traction, especially under slippery road conditions. The
brakes are applied to the spinning wheel and power is
transferred to the wheel(s) with traction.
The traction control engages at vehicle speeds up to
approx. 24 mph (40 km / h), and switches off at
50 mph (80 km / h).
The 4-ETS+ warning lampv, located in the
speedometer dial, starts to flash at any vehicle speed, as
soon as the tires lose traction and the wheels begin to
spin.
Important!
If the 4-ETS+ warning lampv flashes:
•During take-off, apply as little throttle as possible.
•While driving, ease up on the accelerator.
•Adapt your speed and driving to the prevailing road
conditions.4-ETS+ Control
If the yellow 4-ETS+ malfunction indicator lamp{
comes on while the 4-ETS+ warning lampv flashes,
the electronic traction system is being switched off
temporarily to prevent overheating of the drive wheel
brakes.
If the 4-ETS+ malfunction indicator lamp{ comes on
with the engine running, a malfunction has been
detected.
Have the 4-ETS+ checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
With the ABS malfunctioning, the 4-ETS+ is also
switched off.
Caution!
If the vehicle is towed with the front axle raised (see
towing the vehicle on page 277), or when testing the
parking brake on a brake test dynamometer, the engine
must be shut off (key in steering lock position 0 or 1).
Otherwise, the electronic traction system will
immediately be engaged and will apply the rear wheel
brakes.

222 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Note:
In winter operation, the maximum effectiveness of the
electronic traction system is only achieved with
Mercedes-Benz recommended M+S rated radial-ply tires
and / or snow chains.
LOW RANGE – 4-ETS+
During off-road driving a special low range system for
the four wheel electronic traction system (4-ETS+) is
operational with transmission in LOW RANGE mode,
see page 229.
If one or more tires lose traction while driving downhill
(accelerator released), the 4-ETS+ engages and the
warning lampv, located in the speedometer dial,
starts to flash.Electronic brake proportioning (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.
If a warning tone sounds for five seconds and the
symbols É and - are displayed in the instrument
cluster, the system has detected a malfunction and is
switched off. Have the system checked immediately at
an authorized Mercedes-Benz Light Truck Center.
Failure to do so could result in an accident, since the
enhanced braking effect is not available when the
system is switched off.
Note:
When the EBP is switched off, every time the engine is
started, a warning tone will sound for five seconds and
the symbols É and - will light up. In addition,
whenever the brakes are applied at speeds exceeding
25 mph (40 km / h), the warning tone sounds for five
seconds.

223 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Electronic stability program (ESP)
The ESP enhances directional control and reduces
driving wheel spin of the vehicle under various driving
conditions.
Over-/understeering of the vehicle is counteracted by
applying brakes to the appropriate wheel to create a
countervailing vehicle movement. Engine torque is also
limited. The ESP warning lamp, located in the
speedometer dial, starts to flash when ESP is in
operation.Important!
If the ESP warning lampv flashes:
•During take-off apply as little throttle as possible.
•While driving ease up on the accelerator.
•Adapt your speed and driving to the prevailing road
conditions.
•Do not switch off the ESP.
Caution!
If the vehicle is towed with the front axle raised (see
towing the vehicle on page 277), the engine must be
shut off (key in steering lock position 0 or 1). Otherwise,
the ESP will immediately be engaged and will apply the
rear wheel brakes.
Notes:
The malfunction indicator lamp for the ESP is combined
with that of the BAS.
The yellow BAS / ESP malfunction indicator lamp¿
in the instrument cluster and the yellow ESP warning
lampv in the speedometer dial come on with the
key in steering lock position 2. They should go out with
the engine running.
Wa r n i n g !
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, or aquaplaning. Only a safe,
attentive, and skillful driver can prevent accidents.
The capabilities of an ESP equipped vehicle must
never be exploited in a reckless or dangerous
manner which could jeopardize the user’s safety or
the safety of others.

224 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
If the BAS / ESP malfunction indicator lamp¿ comes
on continuously with the engine running, a malfunction
has been detected in either system. Only partial engine
output will be available.
If the BAS malfunctions, the brake system functions in
the usual manner, but without BAS.
If the BAS / ESP malfunction indicator lamp stays
illuminated, have the BAS or ESP checked at your
authorized Mercedes-Benz Light Truck Center as soon
as possible.
With the ABS malfunctioning, the ESP is also switched
off.
Driving the vehicle with varied size tires will cause the
wheels to rotate at different speeds, therefore the ESP
may activate (yellow ESP warning lampv in
speedometer dial comes on). For this reason, all wheels,
including the spare wheel, must have the same tire
outside diameter.
When testing the parking brake on a brake test
dynamometer, the engine must be shut off. Otherwise,
the ESP will immediately be engaged and will apply the
rear wheel brakes.In winter operation, the maximum effectiveness of the
ESP is only achieved with Mercedes-Benz recommended
M+S rated radial-ply tires and / or snow chains.
Synchronizing ESP
If the power supply was interrupted (battery
disconnected or empty), the BAS / ESP malfunction
indicator lamp may be illuminated with the engine
running.
Turn steering wheel completely to the left and then to
the right. The BAS / ESP malfunction indicator lamp
should go out.
If battery voltage drops below 10 volts, the indicator
lamp comes on and the brake assist system (BAS) is
deactivated. If the battery voltage rises and exceeds
10 volts, the BAS / ESP malfunction indicator lamp goes
out, and brake assist system (BAS) is functional again.
After driving off the BAS / ESP malfunction indicator
lamp should go out after approximately 110 - 220 yd
(100 - 200 m).

227 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Transmission control – LOW RANGE mode
The switch is located in the instrument panel.
Important!
When switching to or from the LOW RANGE mode,
observe the following:
•The vehicle must be at a complete standstill.
•The engine speed must not exceed 1500 rpm.Failure to do so may result in transmission / engine
damage not covered by the Mercedes-Benz Limited
Warranty
The LOW RANGE mode should be switched on:
•during off-road driving,
•when crossing waters,
•when towing up or down on steep gradients,
or additional practical hints refer to off-road driving
on page 202.
Important!
Operating the vehicle on a single axle dynamometer
should only be done for briefly testing the brakes. To do
so, turn key in steering lock to position 1.

229 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Important!
During off-road driving a special low range system for
antilock brake system (ABS) and four-wheel electronic
traction system (4-ETS+) are operational with
transmission in the LOW RANGE mode.
In the low range mode the electronic stability program
(ESP) operates in a traction improving fashion
specifically adapted for off-road driving. At speeds
below 27 mph (45 km / h) the ESP assists in over- /
understeering, thus improving vehicle tracking.
If one or more tires lose traction while driving downhill
(accelerator released), the 4-ETS+ engages and the
warning lampv, located in the speedometer dial,
starts to flash.
When applying the service brakes at speeds below
approximately 18 mph (30 km / h), the front wheels are
locked cyclically to shorten the braking distance (dig in
effect). This affects steering the vehicle.Notes:
Driving off or driving up to 3 mph (5 km / h) with the
service brakes applied lightly (to reduce drive wheel
spin), the 4-ETS+ remains engaged. Driving with the
service brakes applied lightly at vehicles speeds above
3 mph (5 km / h), the 4-ETS+ will not engage.
If the indicator lamp blinks fast, one or more switching
conditions were not observed, or the LOW RANGE mode
is defective.
In the case of a defective in the LOW RANGE mode the
transmission shifts in the usual manner. It is not
possible to switch on the LOW RANGE mode.
Have the transmission checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.