PRE-SAFE®takes the following measures
depending on the hazardous situation detected:
Rthe front seat belts are pre-tensioned.
Rif the vehicle skids, the side windows and the
sliding sunroof are closed.
Rvehicles with the memory function: the front-
passenger seat is adjusted if it is in an unfav-
orable position.
Rvehicles with a multicontour seat: the air pres-
sure in the side bolsters of the seat backrest
is increased.
If the hazardous situation passes without result-
ing in an accident, PRE-SAFE
®slackens the belt
pre-tensioning. On vehicles with multicontour
seats, the air pressure in the side bolsters is
reduced again. All settings made by PRE-SAFE
®
can then be reversed.
If the seat belt pre-tensioning is not reduced:
XMove the seat backrest or seat back slightly
when the vehicle is stationary.
The seat belt pre-tensioning is reduced and
the locking mechanism is released.
The seat-belt adjustment is an integral part of
the PRE-SAFE
®convenience function. Informa-
tion about the convenience function can be
found under "Belt adjustment" (
Ypage 48).
PRE-SAFE®PLUS (anticipatory occu-
pant protection system PLUS)
Introduction
PRE-SAFE®PLUS is only available in vehicles
with the Driving Assistance package.
Using the radar sensor system, PRE-SAFE
®
PLUS is able to detect that a head-on or rear-end
collision is imminent. In certain hazardous sit-
uations, PRE-SAFE
®PLUS takes pre-emptive
measures to protect the vehicle occupants.
Important safety notes
The intervention of PRE-SAFE®PLUS cannot
prevent an imminent collision.
The driver is not warned about the intervention
of PRE-SAFE
®PLUS.
PRE-SAFE®PLUS does not intervene if the vehi-
cle is backing up.
When driving, or when parking or exiting a park-
ing space with assistance from Active Parking Assist, PRE-SAFE
®PLUS will not apply the
brakes.
Function
PRE-SAFE®PLUS intervenes in certain situa-
tions if the radar sensor system detects an
imminent head-on or rear-end collision.
PRE-SAFE
®PLUS takes the following measures
depending on the hazardous situation detected:
Rif the radar sensor system detects that a
head-on collision is imminent, the seat belts
are pre-tensioned.
Rif the radar sensor system detects that a rear-
end collision is imminent:
-the brake pressure is increased if the driver
applies the brakes when the vehicle is sta-
tionary.
-the seat belts are pre-tensioned.
The PRE-SAFE®PLUS braking application is can-
celed:
Rif the accelerator pedal is depressed when a
gear is engaged
Rif the risk of a collision passes or is no longer
detected
Rif DISTRONIC PLUS indicates an intention to
pull away
If the hazardous situation passes without result-
ing in an accident, the original settings are
restored.
Automatic measures after an acci-
dent
Immediately after an accident, the following
measures are implemented, depending on the
type and severity of the impact:
Rthe hazard warning lamps are activated
Rthe emergency lighting is activated
Rthe vehicle doors are unlocked
Rthe front side windows are lowered
Rvehicles with a memory function: the electri-
cally adjustable steering wheel is raised
Rthe engine is switched off and the fuel supply
is cut off
Occupant safety59
Safety
Z
The SmartKey centrally locks and unlocks the
following components:
Rthe doors
Rthe tailgate
Rthe fuel filler flap
The turn signals flash once when unlocking and
three times when locking.
You can also set an audible signal to confirm
that the vehicle has been locked. The audible
signal can be activated and deactivated using
the on-board computer (
Ypage 275).
You will receive visual and acoustic locking con-
firmation if all components were able to be
locked.
If activated in COMAND or Audio 20, the locator
lighting also lights up in the dark (see separate
operating instructions).
XTo open the tailgate automatically from
outside the vehicle: press and hold theF
button until the tailgate opens.
Vehicles with KEYLESS-GO or KEYLESS-GO start function and EASY-PACK tailgate:
XTo close the tailgate automatically from
outside the vehicle: if the SmartKey is loca-
ted in the immediate vicinity of the vehicle,
press the Fbutton on the SmartKey.
When the tailgate closes you can then release
the button.
KEYLESS-GO
General notes
Bear in mind that the engine can be started by
any of the vehicle occupants if there is a KEY-
LESS-GO key in the vehicle (
Ypage 148).
Locking/unlocking centrally
You can start, lock or unlock the vehicle using
KEYLESS-GO. To do this, you only need carry the
SmartKey with you. You can combine the func-
tions of KEYLESS-GO with those of a conven-
tional SmartKey. Unlock the vehicle by using
KEYLESS-GO, for instance, and lock it using the
& button on the SmartKey.
The driver's door and the door at which the han-
dle is used, must both be closed. The SmartKey
must be outside the vehicle. When locking or
unlocking with KEYLESS-GO, the distance between the SmartKey and the corresponding
door handle must not be greater than 3 ft (1 m).
KEYLESS-GO checks whether a valid SmartKey
is in the vehicle by periodically establishing a
radio connection between the vehicle and the
SmartKey. This happens:
Rwhen starting the engine
Rwhile driving
Rwhen the external door handles are touched
Rduring convenience closing
XTo unlock the vehicle:
touch the inner sur-
face of the door handle.
XTo lock the vehicle: touch sensor surface :
or ;.
Make sure that you do not touch the inner
surface of the door handle.
XConvenience closing feature: touch
recessed sensor surface ;for an extended
period.
Further information on the convenience closing
feature (
Ypage 92).
If you pull on the handle of the tailgate, only the cargo compartment of the vehicle is unlocked.
Deactivating and activating
If you do not intend to use a SmartKey for an
extended period of time, you can deactivate the
KEYLESS-GO function of the SmartKey. The
SmartKey will then use very little power, thereby
conserving battery power. For the purposes of
activation/deactivation, the vehicle must not be
nearby.
SmartKey79
Opening and closing
Z
XTo deactivate:press the&button on the
SmartKey twice in rapid succession.
The battery check lamp of the SmartKey
flashes twice briefly and lights up once, then
KEYLESS-GO is deactivated (
Ypage 81).
XTo activate: press any button on the Smart-
Key.
or
XInsert the SmartKey into the ignition lock.
KEYLESS-GO and all of its associated features
are available again.
KEYLESS-GO start function
General notes
Bear in mind that the engine can be started by
any of the vehicle occupants if there is a Smart-
Key in the vehicle (
Ypage 148).
Changing the settings of the locking
system
You can change the settings of the locking sys-
tem. This means that only the driver's door and
the fuel filler flap are unlocked when the vehicle
is unlocked. This is useful if you frequently travel
on your own.
XTo change the setting: press and hold down
the % and& buttons simultaneously
for about six seconds until the battery indica-
tor lamp flashes twice (
Ypage 81).
If the setting of the locking system is changed
within the signal range of the vehicle, pressing
the & or% button:
Rlocks or
Runlocks the vehicle
The SmartKey now functions as follows:
XTo unlock: press the%button once.
XTo unlock centrally: press the%button
twice.
XTo lock centrally: press the&button. The KEYLESS-GO function is changed as fol-
lows:
XTo unlock the driver's door:
touch the inner
surface of the door handle on the driver's
door.
XTo unlock centrally: touch the inner surface
of the door handle on the front-passenger
door or the rear door.
XTo lock centrally: touch the outer sensor
surface on one of the door handles
(
Ypage 79).
XTo restore the factory settings: press and
hold down the %and& buttons simul-
taneously for approximately si x se
conds until
the battery check lamp flashes twice
(
Ypage 81).
Mechanical key
General notes
If the vehicle can no longer be locked or
unlocked with the SmartKey or the KEYLESS-GO
key, use the mechanical key.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm sys-
tem will be triggered. Switch off the alarm
(
Ypage 77).
If you unlock the vehicle using the mechanical
key, the fuel filler flap will not be unlocked auto- matically.
XTo unlock the fuel filler flap: insert the
SmartKey into the ignition lock.
Removing the mechanical key
80SmartKey
Opening and closing
Unlocking and opening doors from
the inside
You can open a door from inside the vehicle
even if it has been locked. You can only open the
rear doors from inside the vehicle if they are notsecured by the child-proof locks (
Ypage 65).
If the vehicle has previously been locked from
the outside, opening a door from the inside will
trigger the anti-theft alarm system. Switch off
the alarm (
Ypage 77).
XFront door: pull door handle ;.
If the door is locked, locking knob :pops up.
The door is unlocked and can be opened.
XRear door: pull door handle ;.
If the door is locked, locking knob :pops up
and the door unlocks.
XPull door handle ;again.
The door can be opened.
Centrally locking and unlocking the
vehicle from the inside
You can centrally lock or unlock the vehicle from
the inside. The buttons are located on both front
doors.
XTo unlock: press button :.
XTo lock:press button ;.
If the front-passenger door is closed, the vehi-
cle locks.
Meanwhile, the fuel filler flap will not be locked
or unlocked.
You cannot unlock the vehicle centrally from the
inside if the vehicle has been locked from the
outside.
You can open a front door from inside the vehi-
cle even if it has been locked.
If a locked door is opened from the inside, the
previous unlock status of the vehicle will be
taken into consideration if:
Rthe vehicle was locked using the locking but-
ton for the central locking, or
Rif the vehicle was locked automatically
The vehicle will be fully unlocked if it had previ-
ously been fully unlocked. If only the driver's
door had been previously unlocked, only the
door which has been opened from the inside is
unlocked.
Automatic locking feature
XTo deactivate: press and hold button :for
about five seconds until a tone sounds.
XTo activate: press and hold button ;for
about five seconds until a tone sounds.
If you press one of the two buttons and do not
hear a tone, the relevant setting has already
been selected.
The vehicle is locked automatically when the
ignition is switched on and the wheels are turn-
ing.
Doors85
Opening and closing
Z
You could therefore be locked out if:
Rthe vehicle is being pushed.
Rthe vehicle is being towed.
Rthe vehicle is on a roller dynamometer.
You can also switch the automatic locking func-
tion on and off using the on-board computer
(
Ypage 275).
Power closing
Power closing pulls the doors and tailgate into
their locks automatically even if they are not
completely closed.
XTo power close a door: push the door into
the lock up to the first detent position.
Power closing will pull the door fully closed.
XTo power close the tailgate: lightly press
the tailgate downwards.
Power closing will pull the tailgate fully
closed.
Unlocking the driver's door (mechan-
ical key)
If the vehicle can no longer be locked or
unlocked with the SmartKey or KEYLESS-GO,
use the mechanical key.
XTake the mechanical key out of the SmartKey
(Ypage 80).
XInsert the mechanical key into the lock of the driver's door as far as it will go.
XTurn the mechanical key counter-clockwise
to position 1.
The door is unlocked.
XTurn the mechanical key back and remove it.
XInsert the mechanical key into the SmartKey
(Ypage 81). If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm sys-
tem will be triggered. Switch off the alarm
(
Ypage 77).
Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the
SmartKey or KEYLESS-GO, use the mechanical
key.
XOpen the driver's door.
XClose the front-passenger door, the rear
doors and the tailgate.
XPress the locking button (Ypage 85).
XCheck whether the locking knobs on the
front-passenger door and the rear doors are
still visible. Press down the locking knobs by
hand, if necessary.
XClose the driver's door.
XTake the mechanical key out of the SmartKey
(Ypage 80).
XInsert the mechanical key into the lock of thedriver's door as far as it will go.
XTurn the mechanical key clockwise as far as it
will go to position 1.
XTurn the mechanical key back and remove it.
XMake sure that the doors and the tailgate are
locked.
XInsert the mechanical key into the SmartKey
(Ypage 81).
If you lock the vehicle as described above, the
fuel filler flap is not locked. The anti-theft alarm
system is not armed.
86Doors
Opening and closing
iVehicles with a diesel engine:you can
start the engine without preglow if the engine
is warm.
Using KEYLESS-GO to start the engine
The Start/Stop button can be used to start the
vehicle without inserting the SmartKey into the
ignition lock. The Start/Stop button must be
inserted in the ignition lock and the SmartKey
must be in the vehicle. This mode for starting the
engine operates independently of the ECO
start/stop automatic engine start function.
XDepress the brake pedal and keep it
depressed.
XPress the Start/Stop button once
(Ypage 146).
Vehicles with a gasoline engine: the engine
starts.
Vehicles with a diesel engine: preglow is
activated and the engine starts.
Starting procedure via smartphone
Observe the important safety notes on starting
the engine (Ypage 147).
You can also start your engine via your smart-
phone from outside the vehicle. In this case, the
previously selected climate control setting is
activated. In this way you can cool or heat the
interior of the vehicle before starting the jour-
ney.
Only start the engine via your smartphone if it is
safe to start and run the engine where your vehi-
cle is parked.
Observe the legal stipulations in the area where your vehicle is parked. Engine start via smart-
phone may be limited to certain countries or
regions.
You can execute a maximum of two consecutive
starting attempts via your smartphone. If you
insert the key into the ignition lock, you can
carry out two more starting attempts.
Once you have started the engine, you can
switch the engine off via your smartphone at any
time.
You can only start the engine via your smart-
phone if:
Rthe key is in the ignition lock
Rpark position Pis selected
Rthe accelerator pedal is not depressed
Rthe anti-theft alarm system is not activated
Rthe panic alarm is not activated
Rthe hazard warning lamps are switched off
Rthe hood is closed.
Rthe doors are closed and locked
Rthe windows and sliding sunroof are closed
Also make sure that:
Rthe fuel tank is sufficiently filled
Rthe starter battery is sufficiently charged
GWARNING
Limbs could be crushed or trapped if the
engine is started unintentionally during ser-
vice or maintenance work. There is a risk of
injury.
Always secure the engine against uninten-
tional starting before carrying out mainte-
nance or repair work.
Make sure that the engine cannot be started via
your smartphone before carrying out mainte-
nance or repairs. You can prevent an engine
start via your smartphone, for example, if you:
Rswitch on the hazard warning lamps
Rdo not lock the doors
Ropen the hood
Pulling away
General notes
GWARNING
If the engine speed is above the idling speed
and you engage transmission position Dor R,
the vehicle could pull away suddenly. There is
a risk of an accident.
When engaging transmission position Dor R,
always firmly depress the brake pedal and do not simultaneously accelerate.
Depress the accelerator carefully when pulling
away.
The vehicle locks centrally once you have pulled
away. The locking knobs in the doors drop down.
You can open the doors from the inside at any
time.
You can also deactivate the automatic locking
feature (
Ypage 275).
148Driving
Driving and parking
It is only possible to shift the transmission from
positionPto the desired position if you depress
the brake pedal. Only then is the parking lock
released. If you do not depress the brake pedal,
the DIRECT SELECT lever can still be moved but the parking lock remains engaged.
iUpshifts take place at higher engine speeds
after a cold start. This helps the catalytic con-
verter to reach its operating temperature
more quickly.
Information on the automatic release of the
electric parking brake (
Ypage 179).
Pulling away with a trailer
To ensure that you do not roll backwards when
pulling away on an uphill slope, engage the elec-
tric parking brake.
XPress and hold handle :.
The electric parking brake continues to brake
and prevent the vehicle from rolling back-
wards.
The red F(USA only) or !(Canada
only) indicator lamp in the instrument cluster remains on.
XDepress the accelerator pedal.
XAs soon as the vehicle/trailer combination isheld by the driving force of the engine, release
lever :.
the electric parking brake is released.
The red F(USA only) or !(Canada
only) indicator lamp in the instrument cluster goes out.
Hill start assist
Hill start assist helps you when pulling away for-
wards or in reverse on an uphill gradient. It holds
the vehicle for a short time after you have
removed your foot from the brake pedal. This gives you enough time to move your foot from
the brake pedal to the accelerator pedal and to
depress it before the vehicle begins to roll.
GWARNING
After a short time, hill start assist will no lon-
ger brake your vehicle and it could roll away.
There is a risk of an accident and injury.
Therefore, quickly move your foot from the
brake pedal to the accelerator pedal. Never
leave the vehicle when it is held by hill start
assist.
Hill start assist is not active if:
Ryou are pulling away on a level road or on a
downhill gradient.
Rthe transmission is in position N.
Rthe electric parking brake is applied.
RESP®is malfunctioning.
ECO start/stop function
Introduction
This section describes the ECO start/stop func- tion for all vehicles except PLUG-IN HYBRID
vehicles. Information on the ECO start/stop
function on PLUG-IN HYBRID vehicles
(
Ypage 253).
The ECO start/stop function switches the
engine off automatically if the vehicle is stopped
under certain conditions.
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 and
you 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.
Driving149
Driving and parking
Z
Problems with the engine
ProblemPossible causes/consequences andMSolutions
The engine does not
start. The starter motor
can be heard.RThere is a malfunction in the engine electronics.
RThere is a malfunction in the fuel supply.
Before attempting to start the engine again:
XTurn the SmartKey back to position 0in the ignition lock.
or
XPress the Start/Stop button repeatedly until all indicator lamps in
the instrument cluster go out.
XTry to start the engine again (Ypage 147). Avoid excessively long
and frequent attempts to start the engine as these will drain the
battery.
If the engine does not start after several attempts:
XConsult 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 too weak or
discharged.
XJump-start the vehicle (Ypage 379).
If the engine does not start despite attempts to jump-start it:
XConsult a qualified specialist workshop.
The starter motor was exposed to a thermal load that was too high.
XAllow the starter motor to cool down for approximately two minutes.
XTry to start the engine again.
If the engine still does not start:
XConsult a qualified specialist workshop.
Vehicles with a gasoline
engine:
The engine is not running
smoothly and is misfir-
ing.There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
XOnly depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic converter
and damage it.
XHave the cause rectified immediately at a qualified specialist work-
shop.
The coolant temperature
gage shows a value
above 248 ‡ (120 †).The coolant level is too low. The coolant is too hot and the engine is no
longer being cooled sufficiently.
XStop as soon as possible and allow the engine and the coolant to
cool down.
XCheck the coolant level (Ypage 359). Observe the warning notes
as you do so and add coolant if necessary.
DYNAMIC SELECT controller
This section describes the DYNAMIC SELECT
controller for all vehicles except PLUG- IN HYBRID vehicles. Information on the
DYNAMIC SELECT controller on PLUG-
IN HYBRID vehicles (Ypage 251).
152DYNAMIC SELECT controller
Driving and parking