2018 MERCEDES-BENZ METRIS brake sensor

Useful information
This Operator's Manual describes all models as
well as standard and optional equipment of your
vehicle that were available at the time of going
to print. Country-specific variations are possi-
ble. Note that your vehicle may not be equipped
with all of the described functions. This also
applies to systems and functions relevant to
safety.
Read the information on qualified specialist
workshops (
Ypage 31).
Breaking-in notes
Important safety notes
In certain driving and driving safety systems, the
sensors adjust automatically while a certain dis-
tance is being driven after the vehicle has been
delivered or after repairs. Full system effective- ness is not reached until the end of this teach-in
procedure.
New or replaced brake pads and brake discs
only reach their optimal braking effect after a
few hundred kilometers of driving. Until then,
compensate for this by applying greater force to
the brake pedal.
The first 1000 miles (1500 km)
For the service life and economy of your vehicle
it is crucial that you break in the engine with due
care.
RTherefore, protect the engine for the first
1000 miles (1500 km) by driving at varying
vehicle and engine speeds.
RAvoid overstraining the vehicle and high
engine speeds during this period, e.g. driving
at full throttle. Do not exceed Øof the per-
missible maximum speed for each gear.
RDo not change down a gear manually in order to brake.
RTry to avoid depressing the accelerator pedal
beyond the pressure point (kickdown).
After 1000 miles (1500 km), you can increase
the engine speed gradually and accelerate the
vehicle to full speed.
iYou should also observe these notes on
breaking-in if the engine or parts of the drive
train on your vehicle have been replaced.
Driving
Important safety notes
GWARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or
parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
GWARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or not at all. This could affect, for example, the power steering and the brake
boosting effect. You will require considerably
more effort to steer and brake. There is a risk
of an accident.
Do not switch off the ignition while driving.
GWARNING
If the parking brake has not been fully
released when driving, the parking brake can:
Roverheat and cause a fire
Rlose its hold function.
There is a risk of fire and an accident. Release
the parking brake fully before driving off.
!Warm up the engine quickly. Do not use the
engine's full performance until it has reached
operating temperature.
Only shift the automatic transmission to the
desired drive position when the vehicle is sta-
tionary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery roads.
You could otherwise damage the drive train.
122Driving
Driving and parking

!Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately. Drive
on for a short while. The brakes are cooled down
more quickly in the airflow.
Wet road surfaces
If you have been driving for a long time in heavy
rain without braking, there may be a delayed
response when you first apply the brakes. This
may also occur after driving through a car wash
or deep water.
You must depress the brake pedal more firmly.
Maintain a longer distance to the vehicle in
front.
While paying attention to the traffic conditions,
you should brake the vehicle firmly after driving
on a wet road surface or through a car wash. This
heats the brake discs, so that they dry more
quickly, which protects them against corrosion.
Limited braking performance on salt-
treated roads
When driving on salted roads, salt may start to
build up on the brake disks and brake pads. This can increase braking distances considerably.
Maintain a greater distance to the vehicle in
front.
To remove any build-up of salt that may have
formed:
XApply the brakes at the start of the journey,
occasionally during journey and at the end of
the journey. Make sure that you do not endan-
ger other road users when doing so.
Checking the brake pad thickness
In addition to monitoring using the brake pad
wear sensor, regularly monitor and check all of
the brake pads by performing a visual inspection
to look for pad material wear.
If you are unable to check the brake wear on the
inside of the wheels, remove the wheels with the tools provided.
Make sure that the brake pad material thickness
never falls below 0.12 in (3 mm). Have the brake pads checked and replaced at a qualified spe-
cialist workshop, if necessary. Do not solely rely on the brake pad wear sensor.
It is strongly recommended that you have the
brake pads checked at a qualified specialist
workshop at every service displayed in the main-
tenance interval indicator, prior to long journeys
and whenever the wheels are removed.
New brake discs and brake pads/
linings
New brake pads and brake discs only reach their
optimal braking effect after about 60 miles
(100 kilometers). Until then, compensate for
this by applying greater force to the brake pedal.
For safety reasons, Mercedes-Benz recom-
mends only installing the following brake discs
and brake pads/linings:
Rbrake discs that have been approved by
Mercedes-Benz
Rbrake pads/linings that have been approved
by Mercedes-Benz or are of an equivalent
standard of quality
Other brake discs or brake pads/linings can
compromise the safety of your vehicle.
Always replace all brake discs or brake pads/
linings on an axle at the same time and only have
them replaced at a qualified specialist work-
shop. When replacing the brake discs, always
have the brake pads/linings replaced at the
same time.
Parking brake
GWARNING
If you must brake the vehicle with the parking brake, the braking distance is considerably
longer and the wheels could lock. There is an
increased danger of skidding and accidents.
Only use the parking brake to brake the vehi-
cle when the service brake is faulty. Do not
apply the parking brake too firmly. If the
wheels lock, release the parking brake until
the wheels begin turning again.
When driving on wet roads or dirt-covered sur-
faces, road salt and/or dirt may get into the
parking brake. This causes corrosion and a
reduction of braking force.
In order to prevent this, drive with the parking
brake lightly applied from time to time. When
doing so, drive for a distance of approximately
140Driving tips
Driving and parking

The last speed set remains stored. The last
speed stored is deleted when you switch off the
engine.
Cruise control is deactivated automatically
when:
Ryou apply the brakes
Ryou apply the parking brake and theF
(only USA) or J(only Canada) indicator
lamp in the instrument cluster lights up
Ryou are driving slower than 20 mph (30 km/h)
Ryou shift to neutral iwhile th evehicl eis in
motion
RES P®intervenes or you deactivat eES P®
Rthere is amalfunction in th eES P®or AB Ssys-
te m
If cruise control automatically deactivates, a
warnin gtone sounds and th eCruise
Contro lOffmessage appears briefl yin th edisplay.
The V symbol and th edisplay of th estore d
speed in th eheader or in th estatu sarea of th e
display are then no tshown.
Problems with cruise contro l
The speed cannotbe set when cruise control is
activated.
The display is showin g amessage of high priority
and canno ttherefor esho w a chang ein speed.
XProceed as instructe dby th emessage in th e
display.
COLLISION PREVENTION ASSIST
Gene ral notes
COLLISION PREVENTION ASSIST help syou:
Rto minimiz eth eris kof afront-en dcollision
wit h a detecte dobstacle in th epat hof your
vehicl e
Rto reduce th econsequence sof acollision
wit hth evehicl ein fron t
The system uses rada rsensor sto detec tvehi-
cle sin front.
COLLISION PREVENTION ASSIST consist sof th e
distanc ewarnin gfunction and Adaptive Brake
Assist.
If COLLISION PREVENTION ASSIST is malfunc -
tioning, th edisplay shows acorrespondin gmes -
sage (
Ypage 216).
Distance warning function
Important safety notes
GWARNIN G
The distanc ewarnin gfunction does no treact:
Rto people or animals
Rto oncomin gvehicles
Rto crossin gtraffic
Rwhen cornering
Thus ,th edistanc ewarnin gfunction canno t
provid e awarnin gin all critica lsituations.
There is aris kof an accident.
Always pay careful attention to th etraffic sit -
uation and be read yto brake.
GWARNIN G
The distanc ewarnin gfunction canno talways
clearly identify objects and complex traffic
situations.
In suc hcases, th edistanc ewarnin gfunction
may:
Rgiv ean unnecessary warnin g
Rnotgiv e a warnin g
There is aris kof an accident.
Always pay careful attention to th etraffic sit -
uation and do no trel ysolely on th edistanc e
warnin gfunction .
In particular, th edetection of obstacles can be
impaire din th ecas eof:
Rdir ton th esensor sor anythin gelse coverin g
th esensor s
Rsnow or heav yrain
Rinterferenc efrom other rada rsource s
Rstrongrada rreflections, for example, in park -
in g garages
Ranarrow vehicl etravelin gin front, e.g. a
motorbik e
Ravehicl etravelin gin fron ton adifferen tlin e
Due to th enature of th esystem, particularly
complicate dbut non-critica ldrivin gcondition s
may also caus eth esystem to display awarning.
If you fail to adapt your drivin gstyle, th edis-
tance warnin gfunction can neither reduce th e
ris kof an acciden tno roverride th elaws of phys -
ics .The distanc ewarnin gfunction canno ttak e
146Driving systems
Driving and parking

into account road, weather or traffic conditions.
The distance warning function is only an aid. You
are responsible for the distance to the vehicle in
front, for vehicle speed, braking in good time
and for staying in your lane.
Following damage to the front end of the vehicle,
have the configuration and operation of the
radar sensor checked at a qualified specialist
workshop. This also applies to collisions at slow
speeds where there is no visible damage to the
front of the vehicle.
If you change wheel size, make sure they corre- spond to the correct wheel size category
(
Ypage 279). If the category is changed without
recoding the control units in the vehicle, the
functioning of the distance warning feature may
be impaired. COLLISION PREVENTION ASSIST
may then detect a malfunction and switch itself
off.
Operation
XTo activate/deactivate: activate or deacti-
vate the distance warning function in the on-
board computer (
Ypage 187).
If the distance warning function of COLLISION
PREVENTION ASSIST is activated, the display
shows the Äsymbol:
Rin the header
Rin the Status Overviewof the Assist.menu (Ypage 186)
At speeds up to approx 20 mph (30 km/h) the
display in vehicles with Active Parking Assist
first shows the ístatus indicator. Only up to
a speed of about 20 mph (30 km/h) does the display show the Äsymbol instead of the
í status indicator.
The distance warning function can help you to
minimize the risk of a front-end collision with a
vehicle ahead or reduce the effects of such a
collision. With the help of the radar sensor sys-
tem, the distance warning function can detect
obstacles that are in the path of your vehicle for
an extended period of time. If the distance warn-
ing function detects that there is a risk of a col-
lision, you will be warned visually and, where
necessary, acoustically. Without your interven-
tion, the distance warning function cannot pre-
vent a collision.
The distance warning function issues a warning
at speeds:
Rfrom about 4 mph (7 km/h) if you approach a
vehicle traveling in front or a stationary vehi-
cle too quickly. The ·warning lamp in the instrument cluster then lights up and an inter-
mittent warning tone also sounds.
At speeds up to about 45 mph (70 km/h), the
system also detects stationary obstacles, for
example stopped or parked vehicles.
XBrake immediately until the distance from the
obstacle increases and the risk of a front-end
collision passes.
or
XTake evasive action, provided it is safe to do
so.
Adaptive Brake Assist
General notes
Adaptive Brake Assist evaluates the traffic sit-
uation with the help of the radar sensor system and can detect obstacles which have been in
your vehicle's path for an extended period of
time. From speeds above 4 mph (7 km/h), Adap-
tive Brake Assist aids you in braking during haz-
ardous situations.
Up to a speed of approximately 125 mph
(200 km/h), Adaptive Brake Assist is capable of
reacting to moving obstacles that have already
been detected as such at least once over the
period of observation.
Important safety notes
GWARNING
Adaptive Brake Assist does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rto stationary obstacles
Rwhen cornering
As a result, the Adaptive Brake Assist may not
intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake.
GWARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
Driving systems147
Driving and parking
Z

In such cases, Adaptive Brake Assist can:
Rintervene unnecessarily
Rnot intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
In particular, the detection of obstacles can be
impaired in the case of:
Rdirt on the sensors or anything else covering
the sensors
Rsnow or heavy rain
Rinterference from other radar sources
Rstrong radar reflections, for example, in park-
ing garages
Ra narrow vehicle traveling in front, e.g. a
motorbike
Ra vehicle traveling in front on a different line
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause Adaptive Brake Assist to inter-
vene.
If you fail to adapt your driving style, Adaptive
Brake Assist can neither reduce the risk of acci-
dent nor override the laws of physics. Adaptive
Brake Assist cannot take into account road,
weather or traffic conditions. Adaptive Brake
Assist is only an aid. You are responsible for the
distance to the vehicle in front, for vehicle
speed, braking in good time and for staying in
your lane.
Following damage to the front end of the vehicle,
have the configuration and operation of the
radar sensor checked at a qualified specialist
workshop. This also applies to collisions at slow
speeds where there is no visible damage to the
front of the vehicle.
If you change wheel size, make sure they corre- spond to the correct wheel size category
(
Ypage 279). If the category is changed without
recoding the control units in the vehicle, the
functioning of Adaptive Brake Assist may be
impaired. COLLISION PREVENTION ASSIST may
then detect a malfunction and switch itself off.
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.
Operation
With the help of the radar sensor system, Adap-
tive Brake Assist can detect obstacles that have been in the path of your vehicle for an extended
period of time. Ada

ptive Brake Assist does not
react to stationary obstacles. If Adaptive Brake
Assist detects a risk of collision with a vehicle
traveling in front or with a stationary obstacle,
the system calculates the braking force neces-
sary to avoid this collision. If you apply the
brakes forcefully, Adaptive Brake Assist will
automatically increase the braking force to a
level suitable for the traffic conditions.
XBrake until the distance to the obstacle
increases and the risk of a collision passes.
ABS prevents the wheels from locking.
The brakes function as usual again if:
Ryou release the brake pedal
Rthere is no longer any danger of a collision
Rno obstacle is detected in front of your vehicle
Braking assistance is then ended.
Blind Spot Assist
General notes
Blind Spot Assist monitors the areas on either
side of the vehicle that are not visible to the
driver with two lateral, rear-facing radar sensors
in the bumper. It supports you from speeds of
approximately 20 mph (30 km/h). A warning
display in the exterior mirrors draws your atten-
tion to vehicles detected in the monitored area.
If you then switch on the corresponding turn
signal to change lane, you will also receive an
optical and audible collision warning.
Important safety notes
GWARNING
Blind Spot Assist does not react to:
Rvehicles overtaken too closely on the side,
placing them in the blind spot area
Rvehicles which approach with a large speed
differential and overtake your vehicle
As a result, Blind Spot Assist may not give
warnings in such situations. There is a risk of
an accident.
148Driving systems
Driving and parking

XSelectStatus Overviewin theAssist.menu and display the attention level
(Ypage 186).
The following information is displayed:
Rthe length of the journey since the last break.
Rthe attention level determined by ATTENTION
ASSIST, displayed in a bar display in five levels
from low to high.
Rif ATTENTION ASSIST is unable to calculate
the attention level and cannot output a warn-
ing, the System
Passivemessage appears in
the display. The bar display is then dimmed.
This is the case, for example, if you are pre-
dominantly driving at a speed below 40 mph
(60 km/h) or above 125 mph (200 km/h).
Activating ATTENTION ASSIST
XActivating ATTENTION ASSIST with the on-
board computer:
Ron vehicles without steering wheel buttons
(Ypage 177)
Ron vehicles with steering wheel buttons
(Ypage 187)
For vehicles with steering wheel buttons, the
system determines the attention level of the
driver depending on the setting selected:
Standard: the sensitivity with which the sys-
tem determines the attention level is set to
normal.
Sensitive: the sensitivity is set higher. The
driver is warned earlier.
When ATTENTION ASSIST is switched on and
the vehicle engine is running:
Ron vehicles without steering wheel buttons,
the À indicator lamp in the instrument
cluster lights up
Ron vehicles with steering-wheel buttons, the
display shows the Àsymbol:
-in the status area
-in the Status Overviewof the Assist.menu (Ypage 186)
For vehicles with steering wheel buttons, if you
deactivate ATTENTION ASSIST, the system is
automatically re-activated when you start the
engine. The system sensitivity then corresponds
to the last selection activated – standard or sen-
sitive.
If you switch off ATTENTION ASSIST in a vehicle without steering wheel buttons, the system
remains switched off even after you start the engine. The status of the system after switching
on the engine always corresponds to the status
last selected.
Warning in the display
If the system detects tiredness or increasing
lapses in concentration, the warning
Atten‐
tion Assist: Take a Break!orAttent.Asst: Take Break!is shown in the display.
An additional warning tone sounds.
XIf necessary, take a break.
XConfirm the message by pressing the a
button on the steering wheel.
On long journeys, take regular breaks in good
time to allow yourself to rest. If you do not take
a break and ATTENTION ASSIST continues to
detect increasing lapses in concentration, you
will be warned again after 15 minutes at the
earliest. This will only happen if ATTEN-
TION ASSIST still detects typical indicators of
fatigue or increasing lapses in concentration.
PARKTRONIC
General notes
PARKTRONIC is an electronic parking aid. The
system is equipped with ultrasonic sensors in
the front and rear bumpers to monitor the area
around your vehicle. PARKTRONIC indicates vis-
ually and audibly the distance between your
vehicle and an object.
Your vehicle features two separate sound emit- ters with different frequencies for the warning
tones. The warning ranges in front of and behind
the vehicle are indicated by different warning
tones.
PARKTRONIC is activated automatically when
you:
Rturn the key to position 2in the ignition lock
Rrelease the parking brake and
Rmove the selector lever to position D,N or R
PARKTRONIC is deactivated at speeds above
11 mph (18 km/h). PARKTRONIC is reactivated
at speeds below 10 mph (16 km/h).
Important safety notes
PARKTRONIC is only an aid. It cannot replace
your own awareness of the immediate surround-
ings. You are responsible for safe maneuvering,
Driving systems153
Driving and parking
Z

parking and pulling away. Make sure that there
are no persons, animals or objects in the maneu-
vering area while maneuvering and parking in/
leaving parking spaces.
!Pay particular attention to obstacles above
or below the sensors when parking, such as
flower pots or trailer towbars. PARKTRONIC
does not recognize such objects when they
are in the immediate vicinity of the vehicle.
You could damage the vehicle or objects.
PARKTRONIC can suffer interference from:
Rultrasonic sources such as a truck's
compressed-air brakes, an automatic car
wash or a pneumatic drill
Rattachments to the vehicle, e.g. rear moun-
ted racks
Rnumber plates (vehicle license plates) that
are not affixed flat against the bumper
Rdirty or icy sensors
Remove a detachable trailer coupling if it is no
longer required. PARKTRONIC measures the
minimum detection range to an obstacle from
the bumper, not the ball coupling.
Range of the sensors
PARKTRONIC does not account for obstacles
that are:
Rbeneath its detection range, e.g. persons, ani-
mals or objects
Rabove its detection range, e.g. overhanging
loads, overhangs or truck loading ramps
The sensors must be free of dirt, ice or slush.
Otherwise, they cannot function correctly.
Clean the sensors regularly, taking care not to
scratch or damage them (
Ypage 268).
Front sensors
CenterApprox. 39 in
(100 cm)
CornersApprox. 24 in (60 cm)
Rear sensors
CenterApprox. 47 in
(120 cm)
CornersApprox. 31 in (80 cm)
Minimum distance
CenterApprox. 8 in (20 cm)
CornersApprox. 8 in (20 cm)
If an obstacle is within this range, the corre-
sponding segments of the warning displays light
up and you hear a warning tone. If the distance
falls below the minimum, the distance from an
obstacle may no longer be shown.
154Driving systems
Driving and parking

Towing a trailer
PARKTRONIC detects a coupled trailer if your
vehicle is equipped with the corresponding elec-
trical installations for trailer towing.
PARKTRONIC is deactivated for the rear area
when you establish an electrical connectionbetween your vehicle and a trailer. If you use an
adapter for the socket, remove it from the
socket after detaching the trailer. Otherwise,
PARKTRONIC remains deactivated for the rear
area.
Problems with PARKTRONIC
ProblemPossible causes/consequences and
MSolutions
Only the red segments in
the PARKTRONIC warn-
ing displays are lit.
In addition, a warning
tone sounds for approx.
two seconds
PARKTRONIC is then
deactivated.
The indicator lamp of the
f button lights up
and the red segments in
the PARKTRONIC warn-
ing display go out.PARKTRONIC has malfunctioned and has switched itself off.
XIf problems persist, have PARKTRONIC checked at a qualified spe- cialist workshop.
The PARKTRONIC warn-
ing displays implausible
distances.
For example, all the seg-
ments may be lit even
though there is no obsta-
cle present.The PARKTRONIC sensors are dirty or iced up.
XClean the PARKTRONIC sensors (Ypage 268).
XTurn the key to position 2in the ignition lock.
The license plate or other parts attached near the sensors may not be
secured correctly.
XCheck the license plate and attachment parts near the sensors for
correct seating.
An external radio or ultrasonic source may be causing interference.
XCheck PARKTRONIC functions in a different location.
Active Parking Assist
General notes
Active Parking Assist is an electronic parking
aid. The system uses ultrasound sensors to
measure the road on both sides of the vehicle
and indicates suitable parking spaces. It can
then actively steer and brake the vehicle to help
you to park and exit the parking space.
Active Parking Assist includes the PARKTRONIC
parking aid which indicates visually and audibly the distance between your vehicle and an
obstruction. To do this, PARKTRONIC uses the ultrasonic sensors of the Active Parking Assist
(
Ypage 153).
Important safety notes
Active Parking Assist is only an aid. It is not a
substitute for your attention to the immediate
surroundings. You are responsible for safe
maneuvering, parking and pulling away. Make
sure that no persons, animals or objects are in
the maneuvering range.
When you deactivate PARKTRONIC, Active Park-
ing Assist will also be deactivated.
156Driving system
s
Driving an d parking