
Servicing the brakes
! The brake fluid level may be too low, if: R
if the red brake warning lamp lights up in
the instrument cluster and R
you hear a warning tone while the engine
is running
Observe additional warning messages in
the multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked immedi-
ately. Consult a qualified specialist work-
shop to arrange this.
! A function or performance test should
only be carried out on a 2-axle dynamom-
eter. If you wish to operate the vehicle on
such a dynamometer, please consult a
qualified specialist workshop in advance.
You could otherwise damage the drive train
or the brake system.
! As the ESP ®
system operates automati-
cally, the engine and the ignition must be
switched off (the SmartKey must be in posi-
tion 0 or 1 in the ignition lock) if:R
the electric parking brake is tested on a
brake dynamometer (for a maximum of
ten seconds) R
the vehicle is towed with the front axle
raised.
Braking triggered automatically by ESP ®
may seriously damage the brake system.
All checks and maintenance work on the
brake system must be carried out at a quali-
fied specialist workshop.
Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the function-
ality of your brakes at regular intervals.
You can find a description of Brake Assist
(BAS) on ( Y
page 66).
Mercedes-Benz recommends that you only
have brake pads/linings installed on your vehicle which have been approved for
Mercedes-Benz vehicles or which correspond
to an equivalent quality standard. Brake
pads/linings which have not been approved
for Mercedes-Benz vehicles or which are not
of an equivalent quality could affect your vehi-
cle's operating safety.
Mercedes-Benz recommends that you only
use brake fluid that has been specially
approved for your vehicle by Mercedes-Benz,
or which corresponds to an equivalent quality
standard. Brake fluid which has not been
approved for Mercedes-Benz vehicles or
which is not of an equivalent quality could
affect your vehicle's operating safety.
Checking brake lining thickness You can measure the break pad/lining thick-
ness using a test gage. Color-coding (green or
red) on the test gage allows you to determine
whether the brake pad/lining thickness is still
sufficient. The test gage is in the vehicle docu-
ment wallet in the glove box.
Front wheel178
Driving tips
Driving and parking

detected vehicle turns a corner and reveals
an obstacle or stationary vehicle, DISTRONIC
PLUS will not brake for these.
Crossing vehicles
DISTRONIC PLUS may detect vehicles that
are crossing your lane by mistake. Activating
DISTRONIC PLUS at traffic lights with cross-
ing traffic, for example, could cause your vehi-
cle to pull away unintentionally.
HOLD function
General notes
The HOLD function can assist the driver in the
following situations: R
when pulling away, especially on steep
slopes R
when maneuvering on steep slopes R
when waiting in traffic
The vehicle is kept stationary without the
driver having to depress the brake pedal.
The braking effect is canceled and the HOLD
function deactivated when you depress the
accelerator pedal to pull away. Important safety notes
G WARNING
When leaving the vehicle, it can still roll away
despite being braked by the HOLD function if: R
there is a malfunction in the system or in
the voltage supply. R
the HOLD function has been deactivated by
pressing the accelerator pedal or the brake
pedal, e.g. by a vehicle occupant. R
the electrical system in the engine com-
partment, the battery or the fuses have
been tampered with. R
the battery is disconnected
There is a risk of an accident.
If you wish to exit the vehicle, always turn off
the HOLD function and secure the vehicle
against rolling away.
! If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes automati-
cally in certain situations.
To prevent damage to the vehicle, deacti-
vate DISTRONIC PLUS and the HOLD func-
tion in the following or other similar situa-
tions: R
when towing the vehicle R
in the car wash
Deactivating the HOLD function
( Y
page 194).
Activation conditions
You can activate the HOLD function if: R
the vehicle is stationary R
the engine is running or if it has been auto-
matically switched off by the ECO start/
stop function R
the driver's door is closed or your seat belt
is fastened R
the electric parking brake is released R
DISTRONIC PLUS is deactivated R
the transmission is in position D , R or N on
vehicles with automatic transmission Driving systems 193
Driving and parking Z

Activating/deactivating DSR If you activat e DS R and no spee d has been
set , th e vehicl e decelerate s to 3 mph
(6 km/ h).
Yo u can only activate DSR when driving at
speeds below 20 mph (30 km/h).
Activating DSR X
Press button C .
Indicator lamp D lights up.
The status indicator in the multifunction
display shows, e.g. DSR 6 km/h
.
If the current vehicle speed is too high, the
DSR icon appears in the multifunction dis-
play. You will also see the message: Max.
Speed 30 km/h .
If you enter or exit a parking space using
Active Parking Assist, and press button C ,
indicator lamp D flashes. DSR can then not
be switched on.
Deactivating DSR X
Press button C .
Indicator lamp D goes out.
The DSR symbol appears in the multifunc-
tion display with the Off
message.
DSR switches off automatically if you drive
faster than 22 mph (35 km/h). The DSR sym-
bol appears in the multifunction display with
the Off message. You also hear a warning
tone. Display in the assistance graphic X
Select the Assistance Graphic function
using the on-board computer
( Y
page 227).
When DSR is activated symbol C appears
in the assistance graphics display.
Changing the set speed while the vehi-
cle is in motion
When DSR is activated, you can change the
set speed to a value between 2 mph and
11 mph (Canada: between 4 km/h and
18 km/h) while the vehicle is in motion. X
To increase or decrease in 1 mph incre-
ments (Canada: 1 km/h increments):
briefly press the cruise control lever to the
pressure point, up C for a higher set speed
or down D for a lower set speed.
The set value appears in the status indica-
tor of the multifunction display.198
Driving systems
Driving and parking