engine MERCEDES-BENZ M-Class 2015 W166 Owner's Guide

The shoulder section of the seat belt must
always be routed across the center of the
shoulder. Adjust the belt sash guide if neces-
sary.
X To raise: slide the belt guide upwards.
The belt guide will engage in various posi-
tions.
X To lower: hold belt guide release 0043and
slide the belt guide downwards.
X Let go of belt guide release 0043in the
desired position and make sure that the
belt guide engages.
All seat belts except the driver's seat belt are equipped with a special seat belt retractor to
securely fasten child restraint systems in the
vehicle. Further information can be found
under "Special seat belt retractor"
(Y page 61).
Releasing seat belts !
Make sure that the seat belt is fully rolled
up. Otherwise, the seat belt or belt tongue
will be trapped in the door or in the seat
mechanism. This could damage the door,
the door trim panel and the seat belt. Dam-
aged seat belts can no longer fulfill their
protective function and must be replaced.
Visit a qualified specialist workshop. X
Press release button 0043, hold belt
tongue 0044and guide it back towards belt
outlet 0087.
Seat belt adjustment The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. This
function adjusts the driver's and front-
passenger seat belt to the upper body of the
occupants.
The belt strap is tightened slightly when:
R the belt tongue is engaged in the buckle
and
R the ignition is switched on
The seat-belt adjustment will apply a certain
tightening force if any slack is detected
between the vehicle occupant and the seat
belt. Do not hold on to the seat belt tightly
while it is adjusting.
You can switch the seat-belt adjustment on
and off in the on-board computer
(Y page 280).
Belt warning for the driver and front
passenger The
0076 seat belt warning lamp in the instru-
ment cluster is a reminder that all occupants
must fasten their seat belts. It may light up
continuously or flash. In addition, there may
be a warning tone.
Regardless of whether the driver's and front- passenger seat belts have already been fas-
tened, the 0076seat belt warning lamp lights
up for six seconds each time the engine is
started. If, after six seconds, the driver or
front-passenger seat belt has not been fas-
tened and the doors are closed, the 0076seat
belt warning lamp lights up. As soon as the
driver's and front-passenger seat belts are
fastened or a front door is opened again, the
0076 seat belt warning lamp goes out.
If the driver's seat belt is not fastened after
the engine is started, an additional warning
tone will sound. This warning tone stops after Occupant safety
49Safety Z

R
in vehicles with a memory function: the
electrically adjustable steering wheel is
raised
R the engine is switched off
R vehicles with mbrace: automatic emer-
gency call Children in the vehicle
Important safety notes
Accident statistics show that children
secured in the rear seats are safer than chil-
dren secured in the front-passenger seat. For this reason, Mercedes-Benz strongly advises
that you install a child restraint system on a
rear seat. Children are generally better pro-
tected there.
If a child younger than 12 years and under 5 ft
(1.50 m) in height is traveling in the vehicle:
R always secure the child in a child restraint
system suitable for Mercedes-Benz vehi-
cles. The child restraint system must be
appropriate to the age, weight and size of
the child
R be sure to observe the instructions and
safety notes in this section in addition to
the child restraint system manufacturer's
installation instructions
R be sure to observe the instructions and
safety notes on the "Occupant classifica-
tion system (OCS)" (Y page 53)G
WARNING
If you leave children unsupervised in the vehi- cle, they could set it in motion by, for example:
R release the parking brake.
R shift the automatic transmission out of the
parking position P.
R start the engine.
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury. When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle. G
WARNING
If persons, particularly children are subjected to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle. G
WARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight. Pro- tect it with a blanket, for example. If the child
restraint system has been exposed to direct
sunlight, let it cool down before securing the
child in it. Never leave children unattended in the vehicle.
Always ensure that all vehicle occupants have
their seat belts fastened correctly and are sit- ting properly. Particular attention must be
paid to children.
Observe the safety notes on the seat belt
(Y page 46) and the notes on correct use of
seat belts (Y page 47).
A booster seat may be necessary to achieve
proper seat belt positioning for children over
41 lbs (18 kg) or until they reach a height
where a lap/shoulder belt fits properly with-
out a booster seat. Special seat belt retractor
G
WARNING
If the seat belt is released while driving, the
child restraint system will no longer be
secured properly. The special seat belt retrac- tor is disabled and the inertia real draws in a Children in the vehicle
61Safety
Z

Child-proof locks
Important safety notes G
WARNING
If children are traveling in the vehicle, they
could:
R open doors, thus endangering other people
or road users
R exit the vehicle and be caught by oncoming
traffic
R operate vehicle equipment and become
trapped
There is a risk of an accident and injury.
Always activate the child-proof locks and
override feature if children are traveling in the vehicle. When leaving the vehicle, always take
the key with you and lock the vehicle. Never
leave children unattended in the vehicle.
Override feature for: R the rear doors (Y page 66)
R the rear side windows (Y page 67)G
WARNING
If you leave children unsupervised in the vehi- cle, they could set it in motion by, for example:
R release the parking brake.
R shift the automatic transmission out of the
parking position P.
R start the engine.
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle. G
WARNING
If persons, particularly children are subjected to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle. G
WARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight. Pro- tect it with a blanket, for example. If the childrestraint system has been exposed to direct
sunlight, let it cool down before securing the
child in it. Never leave children unattended in the vehicle.
Child-proof locks for the rear doors You secure each door individually with the
child-proof locks on the rear doors. A door
secured with a child-proof lock cannot be
opened from inside the vehicle. When the
vehicle is unlocked, the door can be opened
from the outside.
X To activate: press the child-proof lock
lever up in the direction of arrow 0043.
X Make sure that the child-proof locks are
working properly.
X To deactivate: press the child-proof lock
lever down in the direction of arrow 0044.66
Children in the vehicleSafety

snow chains. Only in this way will the driv-
ing safety systems described in this section
work as effectively as possible. ABS (Anti-lock Braking System)
General information ABS regulates brake pressure in such a way
that the wheels do not lock when you brake.
This allows you to continue steering the vehi-
cle when braking.
The 0025 ABS warning lamp in the instrument
cluster lights up when the ignition is switched on. It goes out when the engine is running.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 67). G
WARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition-
ally, further driving safety systems are deac-
tivated. There is an increased danger of skid- ding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
When ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information on the ABS warning lamp (Y page 320) and
display messages which may be shown in the
instrument cluster (Y page 285).
ABS works from a speed of about 5 mph
(8 km/h), regardless of road-surface condi-
tions. ABS works on slippery surfaces, even
when you only brake gently. Braking X
If ABS intervenes: continue to depress the
brake pedal vigorously until the braking sit- uation is over.
X To make a full brake application:
depress the brake pedal with full force.
If ABS intervenes when braking, you will feel a
pulsing in the brake pedal.
The pulsating brake pedal can be an indica-
tion of hazardous road conditions, and func-
tions as a reminder to take extra care while
driving.
Off-road ABS An ABS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated (Y page 251).
At speeds below 20 mph (30 km/h), the front
wheels lock cyclically during braking. The dig-
ging-in effect achieved in the process reduces the stopping distance on off-road terrain. This
limits steering capability. BAS (Brake Assist System)
General information BAS operates in emergency braking situa-
tions. If you depress the brake pedal quickly,
BAS automatically boosts the braking force,
thus shortening the stopping distance.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 67). G
WARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking. 68
Driving safety systemsSafety

Should you approach an obstacle and Adap-
tive Brake Assist has detected a risk of colli-
sion, Adaptive Brake Assist calculates the
braking force necessary to avoid a rear-end
collision. Should you apply the brakes vigo-
rously, Adaptive Brake Assist will automati-
cally increase the braking force to a level suit- able for the traffic conditions.
X Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if:
R you release the brake pedal.
R there is no longer any danger of a collision.
R no obstacle is detected in front of your
vehicle.
Adaptive Brake Assist is then deactivated.
Vehicles with PRE-SAFE ®
:if adaptive Brake
Assist requires particularly high brake pres-
sure, preventive passenger protection meas-
ures (PRE-SAFE ®
) are deployed simultane-
ously.
Up to vehicle speeds of around 155 mph
(250 km/h), adaptive Brake Assist is capable
of reacting to moving objects that have
already been recognized as such at least once
over the period of observation. Adaptive
Brake Assist does not react to stationary
obstacles.
If Adaptive Brake Assist is not available due to
a malfunction in the radar sensor system, the brake system remains available with full
brake boosting effect and BAS.
In particular, the detection of obstacles can
be impaired if there is:
R dirt on the sensors or anything else cover-
ing the sensors
R there is snow or heavy rain
R there is interference by other radar sources
R there are strong radar reflections, for
example in parking garages
R a narrow vehicle traveling in front, e.g. a
motorbike R
a vehicle traveling in front on a different line
relative to the center of your vehicle
R new vehicles or after the COLLISION PRE-
VENTION ASSIST system has been serv-
iced
Observe the notes in the section on break- ing-in (Y page 156).
Following damage to the front end of the vehi-
cle, have the configuration and operation of
the radar sensor checked at a qualified spe-
cialist workshop. This also applies to colli-
sions at low speeds where there is no visible
damage to the front of the vehicle. ESP
®
(Electronic Stability Program)
General notes i
Observe the "Important safety notes" sec-
tion (Y page 67).
ESP ®
monitors driving stability and traction,
i.e. power transmission between the tires and
the road surface.
If ESP ®
detects that the vehicle is deviating
from the direction desired by the driver, one
or more wheels are braked to stabilize the
vehicle. The engine output is also modified to keep the vehicle on the desired course within
physical limits. ESP ®
assists the driver when
pulling away on wet or slippery roads. ESP ®
can also stabilize the vehicle during braking.
ETS/4ETS (Electronic Traction System) ETS/4ETS traction control is part of ESP
®
.
Traction control brakes the drive wheels indi- vidually if they spin. This enables you to pull
away and accelerate on slippery surfaces, for
example if the road surface is slippery on one
side. In addition, more drive torque is trans-
ferred to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP ®
.
In appropriate driving situations, activate the
off-road program (Y page 251).72
Driving safety systemsSafety

Off-road 4ETS (Electronic Traction Sys-
tem) A 4ETS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated (Y page 251).
Important safety notes G
WARNING
If ESP ®
is malfunctioning, ESP ®
is unable to
stabilize the vehicle. Additionally, further driv- ing safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP ®
checked at a
qualified specialist workshop.
! Vehicles with 4MATIC: only operate the
vehicle for a maximum of ten seconds on a
brake test dynamometer. Switch off the
ignition.
Application of the brakes by ESP ®
may oth-
erwise destroy the brake system.
! Vehicles with 4MATIC: function or per-
formance tests may only be carried out on
a 2-axle dynamometer. Before you operate the vehicle on such a dynamometer, please
consult a qualified workshop. You could
otherwise damage the drive train or the
brake system.
ESP ®
is deactivated if the 00BBwarning lamp
in the instrument cluster lights up continu-
ously when the engine is running.
If the 00E5 warning lamp and the 00BBwarn-
ing lamp are lit continuously, ESP ®
is not
available due to a malfunction.
Observe the information on warning lamps
(Y page 323) and display messages which
may be shown in the instrument cluster
(Y page 285).
i Only use wheels with the recommended
tire sizes. Only then will ESP ®
function
properly. Characteristics of ESP
® General information
If the
00E5 ESP warning lamp goes out before
beginning the journey, ESP ®
is automatically
active.
If ESP ®
intervenes, the 00E5ESP®
warning
lamp flashes in the instrument cluster.
If ESP ®
intervenes:
X Do not deactivate ESP ®
under any circum-
stances.
X Only depress the accelerator pedal as far as
necessary when pulling away.
X Adapt your driving style to suit the prevail-
ing road and weather conditions.
ECO start/stop function
The ECO start/stop function switches the
engine off automatically when the vehicle
stops moving. The engine starts automati-
cally when the driver wants to pull away again. ESP ®
remains in its previously selected sta-
tus. Example: if ESP®
was deactivated before
the engine was switched off, ESP ®
remains
deactivated when the engine is switched on
again.
Deactivating/activating ESP ® Important safety notes
You can select between the following states
of ESP
®
:
R ESP ®
is activated.
R ESP ®
is deactivated. G
WARNING
If you deactivate ESP ®
, ESP ®
no longer sta-
bilizes the vehicle. There is an increased risk
of skidding and an accident.
Only deactivate ESP ®
in the situations descri-
bed in the following. Driving safety systems
73Safety Z

It may be best to deactivate ESP
®
in the fol-
lowing situations:
R when using snow chains
R in deep snow
R on sand or gravel
i Activate ESP ®
as soon as the situations
described above no longer apply. ESP ®
will
otherwise not be able to stabilize the vehi-
cle if the vehicle starts to skid or a wheel
starts to spin.
! Avoid spinning the driven wheels for an
extended period with ESP ®
deactivated.
You could otherwise damage the drivetrain.
Deactivating/activating ESP ®X
To switch off: press button0043.
The 00BB ESP®
OFF warning lamp in the
instrument cluster lights up.
X To switch on: press button0043.
The 00BB ESP®
OFF warning lamp in the
instrument cluster goes out.
Characteristics when ESP ®
is deactivated
If ESP ®
is deactivated and one or more wheels
start to spin, the 00E5ESP®
warning lamp in
the instrument cluster flashes. In such situa-
tions, ESP ®
will not stabilize the vehicle.
If you deactivate ESP ®
:
R ESP ®
no longer improves driving stability.
R engine torque is no longer limited and the
drive wheels are able to spin. The spinning of the wheels results in a cut-
ting action for better traction on loose sur- faces.
R traction control is still activated.
R ESP ®
still provides support when you
brake.
Off-road ESP ®
(vehicles with Off-Road
Engineering package) An ESP
®
system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated (Y page 251).
Off-road ESP ®
intervenes with a delay if there
is oversteering or understeering, thus improv-
ing traction.
ESP ®
trailer stabilization General information
ESP
®
trailer stabilization is not available in
AMG vehicles.
If your vehicle/trailer combination begins to
swerve, ESP ®
assists you in this situation.
ESP ®
slows the vehicle down by braking and
limiting the engine output until the vehicle/
trailer combination has stabilized.
Important safety notes G
WARNING
If road and weather conditions are poor,
trailer stabilization will not be able to prevent the vehicle/trailer combination from swerv-
ing. Trailers with a high center of gravity can
tip over before ESP ®
can detect this. There is
a risk of an accident.
Always adapt your driving style to the prevail- ing road and weather conditions.
If your vehicle with trailer (vehicle/trailer
combination) begins to lurch, you can only
stabilize the vehicle/trailer combination by
depressing the brake firmly.
Trailer stabilisation is active above speeds of
about 37 mph (60 km/h). 74
Driving safety systemsSafety

STEER CONTROL
General information STEER CONTROL helps you by transmitting a
noticeable steering force to the steering
wheel in the direction required for vehicle
stabilization.
This steering assistance is provided in partic-
ular if:
R both right wheels or both left wheels are on
a wet or slippery road surface when you
brake.
R the vehicle starts to skid.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 67).
No steering support is provided from STEER
CONTROL, if:
R ESP ®
is malfunctioning.
R the lighting is faulty.
Power steering will, however, continue to
function. Theft deterrent locking system
Immobilizer
X To activate with the SmartKey: remove
the SmartKey from the ignition lock.
X To activate with KEYLESS-GO: switch the
ignition off and open the driver's door.
X To deactivate: switch on the ignition.
The immobilizer prevents your vehicle from
being started without the correct SmartKey.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Any-
one can start the engine if a valid SmartKey
has been left inside the vehicle.
i The immobilizer is always deactivated
when you start the engine.
In the event that the engine cannot be star- ted when the starter battery is fully charged, the immobilizer may be faulty.
Contact an authorized Mercedes-Benz
Center or call 1-800-FOR-MERCedes (in the
USA) or 1-800-387-0100 (in Canada). ATA (anti-theft alarm system)
X
To arm: lock the vehicle with the SmartKey
or KEYLESS-GO.
Indicator lamp 0043flashes. The alarm sys-
tem is armed after approximately
15 seconds.
X To deactivate using the SmartKey:
unlock the vehicle with the SmartKey.
or X Insert the SmartKey into the ignition lock.
X To deactivate using KEYLESS-GO: unlock
the vehicle with KEYLESS-GO.
or X Press the Start/Stop button on the dash-
board. The SmartKey must be inside the
vehicle.
A visual and audible alarm is triggered if the
alarm system is armed and you open:
R a door
R the vehicle with the mechanical key
R the tailgate
R the hood Theft deterrent locking system
77Safety Z

Useful information
i This Operator's Manual describes all
models and all standard and optional equip- ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
i Read the information on qualified special-
ist workshops (Y page 29). SmartKey
Important safety notes
G
WARNING
If children are left unsupervised in the vehicle, they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shifting the automatic transmission out of
park position P
R Start the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children. G
WARNING
If persons, particularly children are subjected to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle. G
WARNING
If you attach heavy or large objects to the
SmartKey, the SmartKey could be uninten-
tionally turned in the ignition lock. This could
cause the engine to be switched off. There is a risk of an accident.
Do not attach any heavy or large objects to the
SmartKey. Remove any bulky key rings before
inserting the SmartKey into the ignition lock.
! Keep the SmartKey away from strong
magnetic fields. Otherwise, the remote
control function could be affected.
Strong magnetic fields can occur in the
vicinity of powerful electrical installations.
Do not keep the SmartKey: R with electronic devices, e.g. a mobile
phone or another SmartKey
R with metallic objects, e.g. coins or metal
foil
R inside metallic objects, e.g. a metal case
This can affect the functionality of the
SmartKey.
Do not keep the KEYLESS-GO key in the tem-
perature-controlled cup holder. Otherwise,
the KEYLESS-GO key will not be recognized. SmartKey functions
0043
0037 To lock the vehicle
0044 0054 To open/close the tailgate
0087 0036 To unlock the vehicle
X To unlock centrally: press button0087.80
SmartKeyOpening and closing

If you do not open the vehicle within
approximately 40 seconds of unlocking:
R the vehicle is locked again.
R the theft deterrent locking system is
armed again.
X To lock centrally: press button0043.
The SmartKey centrally locks/unlocks:
R the doors
R the tailgate
R the fuel filler flap
The turn signals flash once when unlocking
and three times when locking.
You can also set an audible signal to confirm that the vehicle has been locked. The audiblesignal can be activated and deactivated using
the on-board computer (Y page 279).
When it is dark, the surround lighting also
comes on if it is activated in the on-board
computer (Y page 278). KEYLESS-GO
General notes Bear in mind that the engine can be started by
any of the vehicle occupants if there is a KEY- LESS-GO key in the vehicle.
Locking/unlocking centrally You can start, lock or unlock the vehicle using
KEYLESS-GO. To do this, you only need carry
the SmartKey with you. You can combine the functions of KEYLESS-GO with those of a con-
ventional SmartKey. Unlock the vehicle by
using KEYLESS-GO, for instance, and lock it
using the 0037button on the SmartKey.
When locking or unlocking with KEYLESS-GO,
the distance between the SmartKey and the
corresponding door handle must not be
greater than 3 ft (1 m). KEYLESS-GO checks whether a valid Smart-
Key is in the vehicle by periodically establish- ing a radio connection between the vehicle
and the SmartKey. This happens:
R when the external door handles are
touched
R when starting the engine
R while the vehicle is in motion X
To unlock the vehicle: touch the inner
surface of the door handle.
X To lock the vehicle: touch sensor sur-
face 0043.
X Convenience closing feature: touch
recessed sensor surface 0044for an exten-
ded period.
Further information on the convenience clos-
ing feature (Y page 95).
If you pull on the handle of the tailgate, only
the cargo compartment of the vehicle is
unlocked. Changing the settings of the locking
system
You can change the settings of the locking
system. This means that only the driver's door and the fuel filler flap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel on your own.
X To change the setting: press and hold
down the 0036and0037 buttons simulta-
neously for approximately six seconds until SmartKey
81Opening and closing Z