
XPress the à button.
The indicator lamp in the ¬ button goes
out. Airflow and air distribution are set to
automatic mode.
or X Turn temperature control : or B counter-
clockwise or clockwise ( Y page 133),
( Y page 136).
or
X Press the K or I button.
MAX COOL maximum cooling
The MAX COOL function is only available in
vehicles for the USA.
MAX COOL is only operational when the
engine is running.
When you activate MAX COOL, climate con-
trol switches to the following functions:
R maximum cooling
R maximum airflow
R air-recirculation mode on
X To activate: press the Ù button.
The indicator lamp in the Ù button lights
up.
X To deactivate: press the Ù button.
The indicator lamp in the Ù button goes
out. The previously selected settings are
restored.
Defrosting the windows
Windows fogged up on the inside
X Activate the ¿ cooling with air dehu-
midification function.
X Activate automatic mode Ã.
X Adjust the side air vents so that the warmed
air is directed to the side windows.
X If the windows continue to fog up, activate
the ¬ "Windshield defrosting" function.
iYou should only select this setting until
the windshield is clear again.
Windows fogged up on the outside
X Activate the windshield wipers.
X Press the _ button repeatedly until the
O or P symbol appears in the dis-
play.
X Adjust the side air vents so that no air is
directed to the side windows.
Rear window defroster
General notes
The rear window defroster has a high current draw. You should therefore switch it off as
soon as the rear window is clear. Otherwise,
the rear window defroster switches off auto-
matically after several minutes.
If the battery voltage is too low, the rear win-
dow defroster may switch off.
Switching on/off
X Turn the SmartKey to position 2 in the igni-
tion lock ( Y page 149).
X Press the ¤ button.
The indicator lamp in the ¤ button lights
up or goes out.
142Operating the climate control systems
Climate control

Problems with the rear window defroster
ProblemPossible causes/consequences and M Solutions
The rear window
defroster has deactiva-
ted prematurely or can-
not be activated.The battery has not been sufficiently charged.
X Switch off any consumers that are not required, e.g. reading
lamps, interior lighting or the seat heating.
When the battery is sufficiently charged, the rear window
defroster can be activated again.
Activating/deactivating air-recircula-
tion mode
General notes
You can deactivate the flow of fresh air if
unpleasant odors are entering the vehicle
from outside. The air already inside the vehi-
cle will then be recirculated.
If you switch on air-recirculation mode, the
windows can fog up more quickly, in particu-
lar at low temperatures. Only use air-recircu-
lation mode briefly to prevent the windows
from fogging up.
Switching on/off
X Turn the SmartKey to position 2 in the igni-
tion lock ( Y page 149).
X To activate: press the g button.
The indicator lamp in the g button lights
up.
iIn the event of high pollution levels 10
or at
high outside temperatures, air-recircula-
tion mode is automatically activated. When
air-recirculation mode is activated auto-
matically, the indicator lamp in the g
button is not lit.
Outside air is added after about
30 minutes.
X To deactivate: press the g button.
The indicator lamp in the g button goes
out.
iAir-recirculation mode deactivates auto-
matically:
R after approximately five minutes at out-
side temperatures below approximately
41 ‡ (5 †)
R after approximately five minutes if cool-
ing with air dehumidification is deactiva-
ted
R after approximately 30 minutes at out-
side temperatures above approximately
41 ‡ (5 †) if the "Cooling with air dehu-
midification" function is activated
Activating/deactivating the residual
heat function
General notes
The residual heat function is only available in vehicles for Canada with 3-zone automatic
climate control.
It is possible to make use of the residual heat
of the engine to continue heating the vehicle
for approximately 30 minutes after the engine
has been switched off. The heating time
depends on the set interior temperature.
iThe blower will run at a low speed regard-
less of the airflow setting.
iIf you activate the residual heat function
at high temperatures, only the ventilation
will be activated. The blower runs at
medium speed.
10 3-zone automatic climate control only.
Operating the climate control systems143
Climate control

Switching on/off
XTurn the key to position 0 in the ignition
lock ( Y page 149) or remove it.
X To activate: press the Ì button.
The indicator lamp in the Ì button lights
up.
iIf the residual heat function is activated,
the windows may fog up on the inside.
X To deactivate: press the Ì button.
The indicator lamp in the Ì button goes
out.
iResidual heat is deactivated automati-
cally:
R after approximately 30 minutes
R when the ignition is switched on
R if the battery voltage drops
Setting the air vents
Important safety notes
GWARNING
Very hot or very cold air can flow from the air
vents. This could result in burns or frostbite in the immediate vicinity of the air vents. There
is a risk of injury.
Make sure that all vehicle occupants always
maintain a sufficient distance to the air out-
lets. If necessary, redirect the airflow to
another area of the vehicle interior.
In order to ensure the direct flow of fresh air
through the air vents into the vehicle interior,
please observe the following notes:
R keep the air inlet between the windshield
and the hood free of blockages, such as ice,
snow or leaves.
R never cover the air vents or air intake grilles
in the vehicle interior.
iFor virtually draft-free ventilation, adjust
the sliders of the air vents to the center
position.
Setting the center air vents
X To open the center air vents: turn the
adjuster in one of center air vents : to the
left.
X To close the center air vents: turn the
adjuster in one of center air vents : to the
right until it engages.
Setting the side air vents
:Side window defroster vent
;Side air vent
X To open a side air vent: turn the adjuster
in the side air vent ; to the left.
X To close a side air vent: turn the adjuster
in the side air vent ; to the right until it
engages.
Setting the glove box air vent
When automatic climate control is activated,
the glove box can be ventilated, for instance
to cool its contents. The level of airflow
144Setting the air vents
Climate control

The engine starts automatically when the
driver wants to pull away again. The ECO
start/stop function thereby helps you to
reduce the fuel consumption and emissions
of your vehicle.
Important safety notes
GWARNING
If the engine is switched off automatically andyou exit the vehicle, the engine is restarted
automatically. The vehicle may begin moving. There is a risk of accident and injury.
If you wish to exit the vehicle, always turn off
the ignition and secure the vehicle against
rolling away.
General notes
If the engine has been switched off automat-
ically by the ECO start/stop function, the ¤ symbol is shown in the multifunction
display.
Every time you switch on the engine using the SmartKey or the Start/Stop button, the ECO
start/stop function is activated.
Automatic engine switch-off
If the vehicle is braked to a standstill in D or N,
the ECO start/stop function switches off the engine automatically.
The ECO start/stop function is operational
when:
R the indicator lamp in the ECO button is lit
green.
R the outside temperature is within the range
that is suitable for the system.
R the engine is at normal operating temper-
ature.
R the set temperature for the vehicle interior
has been reached.
R the battery is sufficiently charged.
R the system detects that the windshield is
not fogged up when the air-conditioning
system is switched on. R
the hood is closed.
R the driver's door is closed and the driver's
seat belt is fastened.
iAll of the vehicle's systems remain active
when the engine is stopped automatically.
iThe HOLD function can also be activated
if the engine has been switched off auto-
matically. It is then not necessary to con-
tinue applying the brakes during the auto-
matic stop phase. When you depress the
accelerator pedal, the engine starts auto-
matically and the braking effect of the
HOLD function is deactivated.
iThe engine can be switched off automat-
ically a maximum of four times (first stop
and three subsequent stops) in succession.
Automatic engine start
The engine starts automatically if:
R you switch off the ECO start/stop function
by pressing the ECO button.
R in transmission position D or N the brake
pedal is released and the HOLD function is not active.
R you depress the accelerator pedal.
R you engage reverse gear R.
R you move the transmission out of position
P.
R you unfasten your seat belt or open the
driver's door.
R the vehicle starts to roll.
R the brake system requires this.
R the temperature in the vehicle interior devi-
ates from the set range.
R the system detects moisture on the wind-
shield when the air-conditioning system is
switched on.
R the battery's condition of charge is too low.
iShifting the transmission to position P
does not start the engine.
Driving153
Driving and parking
Z

Problems with the engine
ProblemPossible causes/consequences and M Solutions
The engine does not
start. The starter motor
can be heard.R
There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.
X Turn the SmartKey back to position 0 in the ignition lock before
attempting to start the engine again.
or
X Press the Start/Stop button repeatedly until all indic ator lamps
in the instrument cluster go out.
X Try to start the engine again ( Y page 151). Avoid excessively
long and frequent attempts to start the engine as these w ill drain
the battery.
If the engine does not start after several attempts: X Consult a qualified specialist workshop.
The engine does not
start. You cannot hear
the starter motor.The on-board voltage is too low because the battery is t oo weak or
discharged.
X Jump-start the vehicle ( Y page 323).
If the engine does not start despite attempts to jump-start it:
X Consult a qualified specialist workshop.
The starter motor was exposed to a thermal load that was t oo high.
X Allow the starter motor to cool down for approximately two
minutes.
X Try to start the engine again.
If the engine still does not start:
X Consult a qualified specialist workshop.
Driving155
Driving and parking
Z

Problems with fuel and the fuel tank
ProblemPossible causes/consequences and M Solutions
Fuel is leaking from the
vehicle.The fuel line or the fuel tank is faulty.
GWARNING
Risk of explosion or fire.
X Turn the SmartKey to position 0 immediately and remove it
( Y page 149).
X Do not restart the engine under any circumstances.
X Consult a qualified specialist workshop.
The engine does not
start.The fuel tank of a vehicle with a diesel engine has been run com-
pletely dry.
X Refuel the vehicle with at least 5.3 US qt (5 liters) of diesel.
X Turn the ignition on for approximately ten seconds
(Y page 149).
X Start the engine continuously for up to ten seconds unt il it runs
smoothly.
If the engine does not start: X Turn the ignition on again for approximately ten seconds
(Y page 149).
X Start the engine again continuously for up to ten seco nds until it
runs smoothly.
If the engine does not start after three attempts:
X Consult a qualified specialist workshop.
The fuel filler flap can-
not be opened.The fuel filler flap is not unlocked.
X Unlock the vehicle ( Y page 78).
The SmartKey battery is discharged or nearly discharged.
X Unlock the vehicle using the mechanical key ( Y page 80).
The fuel filler flap is unlocked, but the opening mecha nism is jam-
med.
X Consult a qualified specialist workshop.
DEF (BlueTEC vehicles only)
Important notes on use
To function properly, BlueTEC exhaust gas
aftertreatment must be operated with the
reducing agent DEF. Adding DEF is one of the tasks performed during maintenance. Under
normal operating conditions, a tank of DEF
lasts until the next service due date.
When the supply of DEF is almost used up, theCheck Additive See Operator's Manual
Refueling165
Driving and parking
Z

iIn the event of an emergency, the engine
can be turned off while the vehicle is in
motion by pressing and holding the Start/
Stop button for three seconds.
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.
GWARNING
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.
If you brake the vehicle with the parking
brake, the brake lamps will not light up.
X To apply: depress parking brake ; firmly.
When the engine is running, the $ (USA
only) or J (Canada only) indicator lamp
lights up in the instrument cluster.
X To release: depress the brake pedal and
keep it depressed.
X Pull release handle :.
When the ignition is switched on or the
engine is running, the $ (USA only) or
J (Canada only) indicator lamp goes out
in the instrument cluster.
Parking the vehicle for a long period
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharging.
If you leave the vehicle parked for longer than six weeks, the vehicle may suffer damage as a
result of lack of use. X Visit a qualified specialist workshop and
seek advice.
iYou can obtain information about trickle
chargers from a qualified specialist work-
shop.
Driving tips
General driving tips
Important safety notes
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 you operate mobile communication equip-
ment while driving, you will be distracted from
Driving tips169
Driving and parking
Z

Stopping
GWARNING
When leaving the vehicle, even if it is braked
only by DISTRONIC PLUS, it could roll away if:R there is a malfunction in the system or in
the voltage supply.
R DISTRONIC PLUS has been deactivated
with the cruise control lever, e.g. by a vehi-
cle occupant or from outside the vehicle.
R the electrical system in the engine com-
partment, the battery or the fuses have
been tampered with.
R the battery is disconnected.
R the accelerator pedal has been depressed,
e.g. by a vehicle occupant.
There is a risk of an accident.
If you wish to exit the vehicle, always turn off
DISTRONIC PLUS and secure the vehicle
against rolling away.
Deactivating DISTRONIC PLUS ( Y page 182).
If DISTRONIC PLUS detects that the vehicle in front is stopping, it brakes your vehicle until it
is stationary.
Once your vehicle is stationary, it remains
stationary and you do not need to depress the
brake.
iDepending on the specified minimum dis-
tance, your vehicle will come to a standstill
at a sufficient distance behind the vehicle in
front. The specified minimum distance is
set using the control on the cruise control
lever.
When DISTRONIC PLUS is activated, the
transmission is shifted automatically to posi- tion P if:
R the driver's door is open and the driver's
seat belt is unfastened.
R the engine is switched off, unless it is auto-
matically switched off by the ECO start/
stop function.
R the hood is opened.
R a system malfunction occurs.
R the power supply is not sufficient.
Setting a speed
XPress the cruise control lever up : for a
higher speed or down ; for a lower speed.
X To adjust the set speed in 1 mph incre-
ments (1 km/h increments): briefly
press the cruise control lever up : or
down ; to the pressure point.
Every time the cruise control lever is
pressed up : or down ; the last speed
stored is increased or reduced.
X To adjust the set speed in 5 mph incre-
ments (10 km/h increments): briefly
press the cruise control lever up : or
down ; beyond the pressure point.
Every time the cruise control lever is
pressed up : or down ;, the last speed
stored is increased or reduced.
iDISTRONIC 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.
Storing the current speed or calling up a
stored speed
X Briefly pull the cruise control lever 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 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 181).
180Driving systems
Driving and parking