1997 MERCEDES-BENZ ML320 brake

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Driving systems
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Instruments
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Driving Instrument
cluster display Practical hints Car care Index
Antilock brake system (ABS)
Important!
The ABS improves steering control of the vehicle during
hard braking maneuvers.
The ABS prevents the wheels from locking up above a
vehicle speed of approximately 5 mph (8 km / h)
independent of road surface conditions.
At the instant one of the wheels is about to lock up, a
slight pulsation can be felt in the brake pedal,
indicating that the ABS is in the regulating mode. Keep
firm and steady pressure on the brake pedal while
experiencing the pulsation.
Continuous steady brake pedal pressure results in
applying the advantages of the ABS, namely braking
power and ability to steer the vehicle. In the case of an emergency brake maneuver keep
continuous full pressure on the brake pedal. In this
manner only can the ABS be most effective.
On slippery road surfaces, the ABS will respond even
with light brake pedal pressure because of the
increased likelihood of locking wheels. The pulsating
brake pedal can be an indication of hazardous road
conditions and functions as a reminder to take extra
care while driving.
ABS control
The ABS malfunction indicator lamp - in the
instrument cluster comes on with the key in steering
lock position 2 and should go out with the engine
running.
When the ABS malfunction indicator lamp - in the
instrument cluster comes on while the engine is
running, it indicates that the ABS has detected a
malfunction and has switched off. In this case, the brake
system functions in the usual manner, but without
antilock assistance.
With the ABS malfunctioning, the BAS, EBP, ESP and
4-ETS+ are also switched off. The malfunction indicator
lamps come on with the engine running.
Wa r n i n g !
Do not pump the brake pedal, rather use firm,
steady brake pedal pressure. Pumping the brake
pedal defeats the purpose for ABS and significantly
reduces braking effectiveness.

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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 211.
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.

203
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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 lamp v 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 4-ETS+ warning lamp v, 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 lamp v 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 lamp v 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 255), 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.

204
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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 211.
If one or more tires lose traction while driving downhill
(accelerator released), the 4-ETS+ engages and the
warning lamp v, located in the speedometer dial,
starts to f lash. 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.

205
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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 lamp v 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 255), 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
lamp v 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.

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Driving systems
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Instruments
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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 lamp v 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.
After driving off the BAS / ESP malfunction indicator
lamp should go out after approximately 110 - 220 yd
(100 - 200 m).

208
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If one drive wheel loses traction and begins to spin, the
brake is applied until the wheel regains sufficient
traction.
Note:
Avoid spinning of one drive wheel. This may cause
serious damage to the drive train which is not covered
by the Mercedes-Benz Limited Warranty.
The ESP warning lamp, located in the speedometer dial,
starts to f lash at any vehicle speed as soon as the tires
lose traction and the wheels begin to spin.
To return to the enhanced vehicle stability offered by
ESP: press lower half of the switch (the ESP warning
lamp in the speedometer dial goes out).
Important!
If the ESP warning lamp f lashes: • during take-off, apply as little throttle as possible,
• while driving, ease up on the accelerator. LOW RANGE – ESP
During off-road driving a special low range system for
the electronic stability program (ESP) is operational
with transmission in LOW RANGE mode, see page 211.
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.

211
Driving systems
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical 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 lamp v, located in the speedometer dial,
starts to f lash.
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.