brake MERCEDES-BENZ A CLASS 2012 Workshop Manual

Storing the current speed and calling up
the last stored speed
G
WARNING
If you call up a stored speed and this is dif-
ferent from the current speed, the vehicle
accelerates or brakes. If you do not know
what the stored speed is, the vehicle may
accelerate or brake unexpectedly. There is a
risk of an accident.
Take the traffic conditions into account
before calling up the stored speed. If you do
not know what the stored speed is, store the
desired speed again.
X Briefly pull the cruise control lever towards
you =.
X Remove your foot from the accelerator
pedal.
The first time cruise control is activated, it
stores the current speed or regulates the
speed of the vehicle to the previously
stored speed.
Setting a speed Keep in mind that it may take a brief moment
until
the vehicle has accelerated or braked to
the set speed.
X Press the cruise control lever up : for a
higher

speed or down ? for a lower speed.
X Keep the cruise control lever pressed until
the desired speed is reached.
X Release the cruise control lever.
The new speed is stored.
X To adjust the set speed in 1 km/h incre-
ments: briefly press the cruise control
lever up : or down ? to the pressure
point.
The

last stored speed increases or decrea-
ses in 1 km/h increments.
X To adjust the set speed in 10 km/h
increments:

press the cruise control lever
briefly up : or down ? beyond the pres-
sure point.
The last stored speed increases or decrea-
ses in 10 km/h increments. i
Cruise control is not deactivated if you
depress the accelerator pedal. For exam-
ple, if you accelerate briefly to overtake,
cruise control adjusts the vehicle's speed
to

the last speed stored after you have fin-
ished overtaking.
Deactivating cruise control There are several ways to deactivate cruise
control:
X
Briefly press the cruise control lever for-
wards B.
or
X Brake
or
X Briefly press the cruise control lever in the
direction of arrow A.
Variable SPEEDTRONIC is selected. LIM
indicator

lamp ; in the cruise control lever
lights up.
Cruise control is automatically deactivated if:
R you engage the electric parking brake.
R you are driving at less than

30 km/h.
R ESP ®
intervenes or you deactivate ESP ®
R while driving a vehicle with manual trans-
mission, you shift into neutral or depress
the clutch pedal for longer than six sec-
onds.
R on vehicles with manual transmission, you
shift to a gear that is too high, and as a
result the engine speed is too low.
R on vehicles with automatic transmission,
you shift into position N while driving.
If cruise control is deactivated, you will hear
a warning tone. You will see the Cruise
control off message in the multifunction
display for approximately five seconds.
i The last speed stored is cleared when you
switch off the engine. 170
Driving systems
Driving and parking

SPEEDTRONIC
Important safety notes SPEEDTRONIC brakes automatically so that
you
do not exceed the set speed. On long and
steep downhill gradients, especially if the
vehicle is laden or towing a trailer, you must
select shift range 1, 2 or 3 in good time. By
doing so, you will make use of the braking
effect of the engine. This relieves the load on
the brake system and prevents the brakes
from overheating and wearing too quickly. If
you need additional braking, depress the
brake pedal repeatedly rather than continu-
ously.
If you fail to adapt your driving style, SPEED-
TRONIC can neither reduce the risk of an
accident nor override the laws of physics.
SPEEDTRONIC cannot take into account
road, weather or traffic conditions. SPEED-
TRONIC is only an aid. You are responsible for
the distance to the vehicle in front, for vehicle
speed, for braking in good time, and for stay-
ing in the lane.
If there is a change of drivers, advise the new
driver of the speed stored.
General notes You can set a variable or permanent limit
speed:
R
variable for speed limits, e.g. in built-up
areas
R permanent for long-term speed restric-
tions, e.g. when driving with winter tyres
fitted (Y page 172)
i The speed indicated in the speedometer
may differ slightly from the limit speed
stored.
Variable SPEEDTRONIC General notes
With

the cruise control lever, you can operate
cruise control or DISTRONIC PLUS and vari-
able SPEEDTRONIC. The LIM indicator lamp on the cruise control
lever

indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control or
DISTRONIC PLUS is selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected.
You can use the cruise control lever to limit
the speed to any speed above 30 km/h while
the engine is running. :
To store the current speed or a higher
speed
; LIM indicator lamp
= To store the current speed and calling up
the last stored speed
? To store the current speed or a lower
speed
A To switch between cruise control or DIS-
TRONIC

PLUS and variable SPEEDTRONIC
B To deactivate variable SPEEDTRONIC
Selecting variable SPEEDTRONIC
X Check whether LIM indicator lamp ;
is on.
If it is on, variable SPEEDTRONIC is already
selected.
If it is not, press the cruise control lever in
the direction of arrow A.
LIM indicator lamp ; in the cruise control
lever lights up. Variable SPEEDTRONIC is
selected.
X Make sure that the accelerator pedal is not
depressed beyond the pressure point. Driving systems
171
Driving and parking Z

Shortly before the stored speed is reached, it
appears in the multifunction display.
Permanent SPEEDTRONIC remains active,
even
if variable SPEEDTRONIC is deactivated.
You cannot exceed the stored limit speed,
even if you depress the accelerator pedal
beyond the pressure point (kickdown). DISTRONIC PLUS
Important safety notes G
WARNING
DISTRONIC PLUS does not react to:
R people or animals
R stationary

obstacles on the road, e.g. stop-
ped or parked vehicles
R oncoming and crossing traffic
As a result, DISTRONIC PLUS may neither give
warnings nor intervene in such situations.
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake. G
WARNING
DISTRONIC PLUS cannot always clearly iden-
tify other road users and complex traffic sit-
uations.
In such cases, DISTRONIC PLUS may:
R give an unnecessary warning and then
brake the vehicle
R neither give a warning nor intervene
R accelerate unexpectedly
There is a risk of an accident.
Continue to drive carefully and be ready to
brake, in particular when warned to do so by
DISTRONIC PLUS. G
WARNING
DISTRONIC PLUS brakes your vehicle with up
to 40% of the maximum braking force. If this
braking

force is insufficient, DISTRONIC PLUS
warns you visually and audibly. There is a risk
of an accident. In such cases, apply the brakes yourself and
try to take evasive action.
! If

DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes automati-
cally in certain situations. To prevent dam-
age to the vehicle, deactivate DISTRONIC
PLUS and the HOLD function in the follow-
ing or other similar situations:
R when towing the vehicle
R in the car wash
If you fail to adapt your driving style, DIS-
TRONIC PLUS can neither reduce the risk of
an accident nor override the laws of physics.
DISTRONIC PLUS cannot take road and
weather conditions or traffic conditions into
account. DISTRONIC PLUS is only an aid. You
are responsible for the distance to the vehicle
in front, for vehicle speed, for braking in good
time, and for staying in the lane.
Do not use DISTRONIC PLUS:
R in road and traffic conditions which do not
allow you to maintain a constant speed
(e.g. in heavy traffic or on winding roads).
R on smooth or slippery roads. Braking or
accelerating can cause the drive wheels to
lose traction and the vehicle could then
skid.
R when there is poor visibility, e.g. due to fog,
heavy rain or snow.
DISTRONIC PLUS may not detect narrow
vehicles driving in front, e.g. motorcycles, or
vehicles driving on a different line.
In particular, the detection of obstacles can
be impaired by:
R dirt on the sensors or anything else cover-
ing the sensors
R snow or heavy rain
R interference by other radar sources
R the possibility of strong radar reflections,
for example, in multi-storey car parks
If DISTRONIC PLUS no longer detects a vehi-
cle in front, it may unexpectedly accelerate to
the speed stored. Driving systems
173
Driving and parking Z

This speed can:
R
be too high for a filter lane or a slip road
R be so high in the right lane that you pass
vehicles driving on the left
R be so high in the left lane that you pass
vehicles driving on the right
If
there is a change of drivers, advise the new
driver of the speed stored.
General notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tance to the vehicle detected in front. DIS-
TRONIC PLUS brakes automatically so that
the set speed is not exceeded.
You

must select a lower gear in good time on
long and steep downhill gradients, especially
if the vehicle is laden or towing a trailer. For
this, you need to have selected manual drive
program M(Y page 166). By doing so, you will
make use of the braking effect of the engine.
This relieves the load on the brake system and
prevents the brakes from overheating and
wearing too quickly.
If a slower-moving vehicle is detected in front,
DISTRONIC PLUS brakes your vehicle. It
maintains the preset distance to the vehicle
in front.
If DISTRONIC PLUS detects that there is a risk
of a collision, you will be warned visually and
acoustically. Without your intervention, DIS-
TRONIC PLUS cannot prevent a collision. An
intermittent warning tone will then sound and
the distance warning lamp will light up in the
instrument cluster. Brake immediately to
increase the distance to the vehicle driving in
front, or take evasive action, provided it is
safe to do so.
The radar sensor system is switched off auto-
matically in the vicinity of radio telescope
facilities ( Y page 350).
For DISTRONIC PLUS to assist you when driv-
ing, the radar sensor system must be:
R activated (Y page 223)
R operational i
In some countries you must deactivate
the radar sensor system ( Y page 223).
For

further information about the radar sen-
sor system; see ( Y page 350).
DISTRONIC PLUS is automatically deactiva-
ted if:
R you are driving slower than 25 km/h and
there is no longer a vehicle in front or
R the vehicle ahead has not been detected
If there is no vehicle in front, DISTRONIC
PLUS operates in the same way as cruise
control in the speed range between
30 km/h and 200 km/h. If a vehicle is driving
in front of you, it operates in the speed range
between 0 km/h and 200 km/h.
Do not use DISTRONIC PLUS on roads with
steep gradients.
Cruise control lever With the cruise control lever, you can operate
DISTRONIC PLUS and variable SPEED-
TRONIC.
The LIM indicator lamp on the cruise control
lever

indicates which system you have selec-
ted:
R LIM indicator lamp off: DISTRONIC PLUS
is selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected. :
To store the current speed or a higher
speed
; To set the specified minimum distance
= LIM indicator lamp174
Driving systems
Driving and parking

?
To store the current speed and calling up
the last stored speed
A To store the current speed or a lower
speed
B To switch between DISTRONIC PLUS and
variable SPEEDTRONIC
C To deactivate DISTRONIC PLUS
Selecting DISTRONIC PLUS
X Check whether LIM indicator lamp = is off.
If it is off, DISTRONIC PLUS is already selec-
ted.
X If it is not, press the cruise control lever in
the direction of arrow B.
LIM

indicator lamp = in the cruise control
lever goes out. DISTRONIC PLUS is selec-
ted.
Activating DISTRONIC PLUS; storing,
maintaining and calling up a speed Activation conditions
To activate DISTRONIC PLUS, all of the fol-
lowing

activation conditions must be fulfilled:
R the engine must be running. It may take up
to two minutes of driving before DIS-
TRONIC PLUS is ready for use.
R the electric parking brake must be
released.
R ESP ®
must be switched on, but not inter-
vening.
R Active Parking Assist must not be activa-
ted.
R the transmission must be in position D.
R the driver's door must be closed when you
shift from P to D or your seat belt must be
fastened.
R the front-passenger door and the rear
doors must be closed.
R the DISTRONIC PLUS function must be
selected with the cruise control lever
(Y page 175). Activating
To

activate while driving: you can only acti-
vate DISTRONIC PLUS at speeds below
20 km/h if the vehicle in front is detected and
shown in the multifunction display. If the vehi-
cle in front is no longer detected and dis-
played, DISTRONIC PLUS switches off and
you will hear a tone.
X Briefly pull the cruise control lever towards
you ? or press it up : or down A.
DISTRONIC PLUS is activated.
X Press the cruise control lever repeatedly
up : or down A until the desired speed
is set.
X Remove your foot from the accelerator
pedal.
Your

vehicle adapts its speed to that of the
vehicle in front, but only up to the desired
stored speed.
When driving at speeds below 30 km/h, you
can
only activate DISTRONIC PLUS if the vehi-
cle in front has been detected and is shown
in the multifunction display. If the vehicle in
front is no longer detected and displayed,
DISTRONIC PLUS switches off and you will
hear a tone.
i If you do not fully release the accelerator
pedal, the DISTRONIC PLUS inactive
message appears in the multifunction dis-
play. The set distance to a slower-moving
vehicle in front will then not be maintained.
You will be driving at the speed you deter-
mine by the position of the accelerator
pedal. Displaying DISTRONIC PLUS in the speedometer Driving systems
175
Driving and parking Z

When DISTRONIC PLUS is activated, one or
two
segments ; in the set speed range light
up.
i For design reasons, the speed displayed
in the speedometer may differ slightly from
the speed set for DISTRONIC PLUS.
If DISTRONIC PLUS detects a vehicle in front,
segments ; between speed of the vehicle in
front : and stored speed = light up.Assistance graphic in vehicles with a colour multi-
function display
:
Vehicle in front, if detected
; Specified minimum distance to the vehi-
cle in front; adjustable
= Own vehicle
? DISTRONIC PLUS active (text only
appears when the cruise control lever is
actuated)
In the Assistance menu (Y page 217) of the
on-board
computer, you can select the assis-
tance graphic.
X Select the Distance display function
using the on-board computer
(Y page 217).
i You
will see the stored speed for approx-
imately five seconds when you activate
DISTRONIC PLUS.
Activating at the current speed/last
stored speed G
WARNING
If you call up a stored speed and this is dif-
ferent from the current speed, the vehicle
accelerates or brakes. If you do not know what the stored speed is, the vehicle may
accelerate or brake unexpectedly. There is a
risk of an accident.
Take the traffic conditions into account
before calling up the stored speed. If you do
not know what the stored speed is, store the
desired speed again.
X Briefly pull the cruise control lever
(Y page 174) towards you ?.
X Remove your foot from the accelerator
pedal.
DISTRONIC PLUS is activated. The first
time it is activated, the current speed is
stored.

Otherwise, it sets the vehicle cruise
speed to the previously stored value.
Setting a speed Keep in mind that it may take a brief moment
until

the vehicle has accelerated or braked to
the set speed. :
To store the current speed or a higher
speed
; To store the current speed or a lower
speed
X Press the cruise control lever up : for a
higher

speed or down ; for a lower speed.
X Keep the cruise control lever pressed until
the desired speed is reached.
X Release the cruise control lever.
The

new speed is stored. DISTRONIC PLUS
is activated and adjusts the vehicle's speed
to the new speed stored. 176
Driving systems
Driving and parking

X
To adjust the set speed in 1 km/h incre-
ments: briefly press the cruise control
lever up : or down ; to the pressure
point.
The
last stored speed increases or decrea-
ses in 1 km/h increments.
X To adjust the set speed in 10 km/h
increments:

press the cruise control lever
briefly up : or down ; beyond the pres-
sure point.
The last stored speed increases or decrea-
ses in 10 km/h increments.
i DISTRONIC
PLUS is not deactivated if you
depress the accelerator pedal. If you accel-
erate to overtake, DISTRONIC PLUS
adjusts the vehicle's speed to the last
speed stored after you have finished over-
taking.
Setting the specified minimum distance You can set the specified minimum distance
for

DISTRONIC PLUS by varying the time span
between one and two seconds. With this func-
tion, you can set the minimum distance that
DISTRONIC PLUS keeps to the vehicle in
front, dependent on vehicle speed. You can
see this distance in the multifunction display
(Y page 175).
i Make sure that you maintain the mini-
mum distance to the vehicle in front as
required by law. Adjust the distance to the
vehicle in front if necessary. X
To increase: turn control = in direc-
tion ;.
DISTRONIC

PLUS then maintains a greater
distance between your vehicle and the
vehicle in front.
X To decrease: turn control = in direc-
tion :.
DISTRONIC

PLUS then maintains a shorter
distance between your vehicle and the
vehicle in front.
Deactivating DISTRONIC PLUS There are several ways to deactivate DIS-
TRONIC PLUS:
X
Briefly press the cruise control lever for-
wards :.
or
X Brake, unless the vehicle is stationary.
or
X Briefly press the cruise control lever in the
direction of arrow =.
Variable SPEEDTRONIC is selected. LIM
indicator

lamp ; in the cruise control lever
lights up.
When you deactivate DISTRONIC PLUS, you
will see the DISTRONIC PLUS off message
in

the multifunction display for approximately
five seconds.
i The last speed stored remains stored until
you switch off the engine. DISTRONIC PLUS
is not deactivated if you depress the accel-
erator pedal. Driving systems
177
Driving and parking Z

DISTRONIC PLUS is automatically deactiva-
ted if:
R
you apply the electric parking brake or if
the vehicle is automatically secured with
the electric parking brake
R you are driving slower than
10 km/h and
there is no longer a vehicle in front, or if the
vehicle in front is no longer detected
R ESP ®
intervenes or you deactivate ESP ®
R the transmission is in the P, R or N position
R you switch off the radar sensor system
R you pull the cruise control lever towards
you in order to pull away and the front-
passenger door or one of the rear doors is
open
R the vehicle is skidding
R you activate Active Parking Assist
If DISTRONIC PLUS is deactivated, you will
hear a warning tone. You will see the DIS‐
TRONIC PLUS off message in the multifunc-
tion display for approximately five seconds.
In the Assistance menu (Y page 217) of the
on-board computer, you can select the assis-
tance graphic. :
Vehicle in front, if detected
; Distance indicator: current distance to
the vehicle in front
= Specified minimum distance to the vehi-
cle in front; adjustable
? Own vehicle
X Select the Distance display function
using the on-board computer
(Y page 217). Tips for driving with DISTRONIC PLUS General notes
The

following contains descriptions of certain
road and traffic conditions in which you must
be particularly attentive. In such situations,
brake if necessary. DISTRONIC PLUS is then
deactivated.
Cornering, going into and coming out of a
bend The ability of DISTRONIC PLUS to detect vehi-
cles when cornering is limited. Your vehicle
may brake unexpectedly or late.
Vehicles

which are not driving in the mid-
dle of their lane DISTRONIC PLUS may not detect vehicles
which are not driving in the middle of their
lane. The distance to the vehicle in front will
be too short.178
Driving systems
Driving and parking

Other vehicles changing lane
DISTRONIC PLUS has not detected the vehi-
cle
cutting in yet. The distance to this vehicle
will be too short.
Narrow vehicles DISTRONIC PLUS has not yet detected the
vehicle in front on the edge of the carriage-
way, because of its narrow width. The dis-
tance

to the vehicle in front will be too short.
Obstructions and stationary vehicles DISTRONIC PLUS does not brake for obsta-
cles

or stationary vehicles. If, for example, the 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
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 is deactivated by the
accelerator pedal being depressed, e.g. by
a vehicle occupant
R the electrical system in the engine com-
partment, the battery or the fuses are tam-
pered with
R the battery is disconnected
There is a risk of an accident.
Before leaving the vehicle, always deactivate
the HOLD function and secure the vehicle
from rolling away. Driving systems
179
Driving and parking Z

!
If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes automati-
cally in certain situations. To prevent dam-
age to the vehicle, deactivate DISTRONIC
PLUS and the HOLD function in the follow-
ing or other similar situations:
R when towing the vehicle
R in the car wash
Deactivate the HOLD function (Y page 180).
General notes The HOLD function can assist the driver in the
following situations:
R
when pulling away, especially on steep
slopes
R when manoeuvring 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 cancelled and the HOLD
function is deactivated when you depress the
accelerator pedal to pull away.
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 if your seat
belt is fastened
R the electric parking brake is released
R the transmission is in position D, R or N on
vehicles with automatic transmission
R DISTRONIC PLUS is deactivated Activating the HOLD function Example: vehicles with colour multifunction display
X
Make sure that the activation conditions
are met.
X Depress the brake pedal.
X Quickly depress the brake pedal further
until : appears in the multifunction dis-
play.
The HOLD function is activated. You can
release the brake pedal.
i If depressing the brake pedal the first
time does not activate the HOLD function,
wait briefly and then try again.
Deactivating the HOLD function The HOLD function is deactivated automati-
cally if:
R
you

accelerate. On vehicles with automatic
transmission: only when the transmission
is in position D or R.
R the transmission is in position P on vehicles
with automatic transmission.
R you depress the brake pedal again with a
certain amount of pressure until : disap-
pears from the multifunction display.
R you secure the vehicle using the electric
parking brake.
R you activate DISTRONIC PLUS.
i After a short period the vehicle is secured
by the electric parking brake, thus relieving
the service brake. 180
Driving systems
Driving and parking