2020 MERCEDES-BENZ METRIS sensor

of the journey. Make sure that you do not
endanger 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 inspec-
tion 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 thick-
ness never falls below
0.12 in (3 mm). Have
the brake pads checked and replaced at a
qualified specialist workshop, if necessary.
Do not solely rely on the brake pad wear sen-
sor.
It is strongly recommended that you have the
brake pads checked at a qualified specialist
workshop at every service displayed in the
maintenance 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, compen-
sate 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:
R brake discs that have been approved by
Mercedes-Benz
R brake 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
workshop. When replacing the brake discs,
always have the brake pads/linings replaced
at the same time. Parking brake G
WARNING
If you must brake the vehicle with the park-
ing brake, the braking distance is considera-
bly longer and the wheels could lock. There
is an increased danger of skidding and acci-
dents.
Only use the parking brake to brake the
vehicle 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
110 yds (100 m) at a maximum speed of
12 mph (20 km/h

).
The brake lamps are not illuminated when you
brake the vehicle using the parking brake. Driving in wet conditions
Hydroplaning G
WARNING
There is a danger of hydroplaning occurring,
even if you are driving slowly and your tires
have sufficient tread depth, depending on
the depth of water on the road. There is a
risk of an accident.
For this reason, avoid tire ruts and brake
carefully.
Therefore, in heavy rain or other conditions in
which hydroplaning can occur, drive as fol-
lows:
R reduce your speed
R avoid tire ruts
R apply the brakes with care Driving tips
143
Driving and parking Z

R
you shift to neutral i while the vehicle is in
motion
R ESP ®
intervenes or you deactivate ESP ®
R there is a malfunction in the ESP ®
or ABS
system
If cruise control automatically deactivates, a
warning tone sounds and the Cruise Con‐
trol Off message appears briefly in the dis-
play.
The V symbol and the display of the stored
speed in the header or in the status area of
the display are then not shown.
Problems with cruise control The speed cannot be set when cruise control
is activated.
The display is showing a message of high pri-
ority and cannot therefore show a change in
speed.
X Proceed as instructed by the message in the
display. COLLISION PREVENTION ASSIST
General notes COLLISION PREVENTION ASSIST helps you:
R to minimize the risk of a front-end collision
with a detected obstacle in the path of your
vehicle
R to reduce the consequences of a collision
with the vehicle in front
The system uses radar sensors to detect vehi-
cles in front.
COLLISION PREVENTION ASSIST consists of
the distance warning function and Adaptive
Brake Assist.
If COLLISION PREVENTION ASSIST is malfunc-
tioning, the display shows a corresponding
message
(Y page 222). Distance warning function Important safety notes
G
WARNING
The distance warning function does not
react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
The distance warning function may not give
warnings in all critical situations. There is a
risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake.
Always adapt your speed to suit the prevail-
ing road and traffic conditions. G
WARNING
The distance warning function cannot
always clearly identify objects and complex
traffic situations.
In such cases, the distance warning function
may:
R give an unnecessary warning
R not give a warning
There is a risk of an accident.
Always pay careful attention to the traffic
situation and do not rely solely on the dis-
tance warning function.
In particular, the detection of obstacles can be
impaired in the case of: R dirt on the sensors or anything else covering
the sensors
R snow or heavy rain
R interference from other radar sources
R 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
Due to the nature of the system, particularly
complicated but non-critical driving conditions Driving systems
149
Driving and parking Z

may also cause the system to display a warn-
ing.
If you fail to adapt your driving style, the dis-
tance warning function can neither reduce the
risk of an accident nor override the laws of
physics. The distance warning function cannot
take into account road, weather or traffic con-
ditions. 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 vehi-
cle, have the configuration and operation of
the radar sensor checked at a qualified spe-
cialist workshop. This also applies to collisions
at slow speeds where there is no visible dam-
age to the front of the vehicle.
If you change wheel size, make sure they cor-
respond to the correct wheel size category
(Y page
278). If the category is changed with-
out 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
X To activate/deactivate: activate or deacti-
vate the distance warning function in the on-
board computer

(Y page 190).
If the distance warning function of COLLI-
SION PREVENTION ASSIST is activated, the
display shows the Ä symbol:
R in the header
R in the Status Overview of the Assist.
menu (Y page 189)
At speeds up to approx 20 mph (30 km/h)
the display in vehicles with Active Parking
Assist first shows the í status indicator.
Only from a speed of about 20 mph
(30 km/h) does the display show the
Äsymbol instead of the í status indica-
tor.
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
warning function detects that there is a risk of
a collision, you will be warned visually and,
where necessary, acoustically. Without your intervention, the distance warning function
cannot prevent a collision.
The distance warning function issues a warn-
ing at speeds:
R from about

4 mph (7 km/h) if you approach
a vehicle traveling in front or a stationary
vehicle too quickly. The · warning lamp
in the instrument cluster then lights up and
an intermittent warning tone also sounds.
At speeds up to about 45 mph (70 km/h),
the system also detects stationary obsta-
cles, for example stopped or parked vehi-
cles.
X Brake immediately until the distance from
the obstacle increases and the risk of a
front-end collision passes.
or X Take 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 sys-
tem 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

),
Adaptive Brake Assist aids you in braking dur-
ing hazardous 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 G
WARNING
Adaptive Brake Assist does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R to stationary obstacles
R when cornering
As a result, the Adaptive Brake Assist may
not intervene in all critical conditions. There
is a risk of an accident. 150
Driving systems
Driving and parking

Always pay careful attention to the traffic
situation and be ready to brake. G
WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist can:
R intervene unnecessarily
R not intervene
There is a risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake. Terminate
the intervention in a non-critical driving sit-
uation.
In particular, the detection of obstacles can be
impaired in the case of:
R dirt on the sensors or anything else covering
the sensors
R snow or heavy rain
R interference from other radar sources
R 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
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
accident 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 vehi-
cle, have the configuration and operation of
the radar sensor checked at a qualified spe-
cialist workshop. This also applies to collisions
at slow speeds where there is no visible dam-
age to the front of the vehicle.
If you change wheel size, make sure they cor-
respond to the correct wheel size category
(Y page
278). If the category is changed with- out 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,
Adaptive Brake Assist can detect obstacles
that have been in the path of your vehicle for
an extended period of time. Adaptive Brake
Assist does not react to stationary obstacles.
If Adaptive Brake Assist detects a risk of colli-
sion with a vehicle traveling in front or with a
stationary obstacle, the system calculates the
braking force necessary 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.
X Brake 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:
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 vehi-
cle
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 sen-
sors in the bumper. It supports you from
speeds of approximately

20 mph (30 km/h). A
warning display in the exterior mirrors draws
your attention to vehicles detected in the
monitored area. If you then switch on the cor-
responding turn signal to change lane, you will
also receive an optical and audible collision
warning. Driving systems
151
Driving and parking Z

Important safety notes
G
WARNING
Blind Spot Assist does not react to:
R vehicles overtaken too closely on the side,
placing them in the blind spot area
R vehicles which approach with a large
speed differential and overtake your vehi-
cle
As a result, Blind Spot Assist may not give
warnings in such situations. There is a risk
of an accident.
Always observe the traffic conditions care-
fully, and maintain a safe lateral distance.
Blind Spot Assist is only an aid. It may fail to
detect some vehicles and is no substitute for
attentive driving. Always ensure that there is
sufficient distance to the side for other road
users and obstacles.
In particular, the detection of obstacles can be
impaired in the case of:
R dirt on the sensors or anything else covering
the sensors
R fog, heavy rain or snow
R narrow vehicles, e.g. motorcycles or bicy-
cles
R very wide lanes
R narrow lanes
R vehicles not driving in the middle of their
lane
R barriers or other road boundaries
Vehicles in the monitoring range are then not
indicated.
i USA only:
This device has been approved by the FCC
as a "Vehicular Radar System". The radar
sensor is intended for use in an automotive
radar system only. Removal, tampering, or
altering of the device will void any warran-
ties, and is not permitted by the FCC. Do
not tamper with, alter, or use in any non-
approved way.
Any unauthorized modification to this device
could void the user’s authority to operate
the equipment. Monitoring range of the sensors
Blind Spot Assist monitors the area shown in
the diagram up to
118 in (3 m) behind and
directly next to your vehicle.
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may
be indicated, especially if the vehicles are not
driving in the middle of their lane. This may be
the case if the vehicles are driving on the inner
side of their lane.
Due to the nature of the system:
R warnings may be issued in error when driv-
ing close to crash barriers or similar solid
lane borders.
R warnings may be interrupted when driving
alongside long vehicles, e.g. trucks, for a
prolonged time.
The two sensors for Blind Spot Assist are inte-
grated into the sides of the rear bumper. Make
sure that the bumper is free of dirt, ice or
slush in the vicinity of the sensors. The radar
sensors must not be covered, for example by
rear-mounted cycle racks or overhanging
loads. Following a severe impact or in the
event of damage to the bumper, have the func-
tion of the radar sensors checked at a quali-
fied specialist workshop. Blind Spot Assist
may otherwise not work properly. 152
Driving systems
Driving and parking

For vehicles with steering wheel buttons you
can have the current ATTENTION ASSIST
(Attention Level) assessment displayed.
X Select Status Overview in the Assist.
menu and display the attention level
(Y page
189).
The following information is displayed: R the length of the journey since the last
break.
R the attention level determined by ATTEN-
TION ASSIST, displayed in a bar display in
five levels from low to high.
R if ATTENTION ASSIST is unable to calculate
the attention level and cannot output a
warning, the System Passive message
appears in the display. The bar display is
then dimmed. This is the case, for example,
if you are predominantly driving at a speed
below

40 mph (60 km/h) or above 125 mph
(200 km/h).
Activating ATTENTION ASSIST X
Activating ATTENTION ASSIST with the on-
board computer:
R on vehicles without steering wheel but-
tons

(Y page 180)
R on vehicles with steering wheel buttons
(Y page 190)
For vehicles with steering wheel buttons,
the system determines the attention level of
the driver depending on the setting selec-
ted:
Standard: the sensitivity with which the
system 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: R on vehicles without steering wheel buttons,
the À indicator lamp in the instrument
cluster lights up
R on vehicles with steering-wheel buttons, the
display shows the À symbol:
- in the status area
- in the Status Overview of the Assist.
menu (Y page

189)
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 corre-
sponds to the last selection activated – stand-
ard or sensitive.
If you switch off ATTENTION ASSIST in a vehi-
cle without steering wheel buttons, the system
remains switched off even after you start the
engine. The status of the system after switch-
ing 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! or Attent.
Asst: Take Break!is shown in the display.
An additional warning tone sounds.
X If necessary, take a break.
X Confirm 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 contin-
ues to detect increasing lapses in concentra-
tion, 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
visually and audibly the distance between your
vehicle and an object.
Your vehicle features two separate sound
emitters with different frequencies for the
warning tones. The warning ranges in front of
and behind the vehicle are indicated by differ-
ent warning tones.
PARKTRONIC is activated automatically when
you:
R turn the key to position 2 in the ignition lock
R release the parking brake and
R move the selector lever to position D, N or R156
Driving systems
Driving and parking

PARKTRONIC is deactivated at speeds above
11 mph (18 km/h
). PARKTRONIC is reactiva-
ted 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 sur-
roundings. You are responsible for safe
maneuvering, parking and pulling away. Make
sure that there are no persons, animals or
objects in the maneuvering area while maneu-
vering 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:
R ultrasonic sources such as a truck's
compressed-air brakes, an automatic car
wash or a pneumatic drill
R attachments to the vehicle, e.g. rear
mounted racks
R number plates (vehicle license plates)
that are not affixed flat against the
bumper
R dirty 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:
R beneath its detection range, e.g. persons,
animals or objects
R above its detection range, e.g. overhanging
loads, overhangs or loading ramps of trucks 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 (Y page

267).
Front sensors Center Approx. 39 in
(100 cm

) Corners Approx. 24 in
(60 cm

) Rear sensors
Center Approx. 47 in
(120 cm

) Corners Approx. 31 in
(80 cm

) Minimum distance
Center Approx. 8 in (20 cm)
Corners Approx. 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 dis- Driving systems
157
Driving and parking Z

tance from an obstacle may no longer be
shown.
Warning displays Front area warning display in center of dashboard
Rear area warning display on the dashboard
Rear area warning display in center of the head-
liner in the rear compartment.
:
Warning segments for the left side of the
vehicle
; Warning segments for the right side of the
vehicle
= Segments showing operational readiness
The warning displays show the distance
between the sensor and the obstacle. The warning display is divided into five yellow
and two red segments for each side of the
vehicle. PARKTRONIC is operational if opera-
tional readiness indicator = lights up.
There is a malfunction if only the red segments
of the warning display light up
(Y page 159).
The selected transmission position determines
whether the front and/or rear area is moni-
tored. Selector lever posi-
tion Monitoring
h
Front area
k or i Front and rear area
j
No areas activated
One or more segments light up as the vehicle
approaches an obstacle, depending on the
vehicle's distance from the obstacle. In addi-
tion, warning tones are emitted.
When the distance to the obstacle is sufficient,
you will hear an intermittent warning tone.
When the distance to the obstacle is sufficient,
you will hear an intermittent warning tone.
When the minimum distance is reached, you
hear a continuous warning tone.
Roll-back warning Regardless of transmission position,
PARKTRONIC automatically monitors the area
behind the vehicle if the vehicle begins to roll
backwards, e.g. after stopping on an uphill gra-
dient.
Activating/deactivating PARKTRONIC X
Press the f button.
If PARKTRONIC is deactivated, the indicator
lamp in the switch lights up.158
Driving systems
Driving and parking