ignition MERCEDES-BENZ S CLASS 2017 Service Manual

If you lock the vehicle centrally using the button
on the front door ( Y
page 83), you can continue
to start the engine with the Start/Stop button.
The engine can be switched off while the vehicle
is in motion by pressing and holding the Start/
Stop button for three seconds. This function
operates independently of the ECO start/stop
automatic engine switch-off function.
Key positions with the Start/Stop button
C
Start/Stop buttonD
Ignition lock
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up. Warning and indicator lamps: see
( Y
page 258).
If Start/Stop button C has not yet been
pressed, this corresponds to the SmartKey
being removed from the ignition. X
To switch on the power supply: press
Start/Stop button C once.
The power supply is switched on. You can now
activate the windshield wipers, for example.
The power supply is switched off again if: R
the driver's door is opened and R
you press Start/Stop button C twice when in
this position X
To switch on the ignition: press Start/Stop
button C twice.
The ignition is switched on.
The ignition is switched off again if: R
you do not start the engine within 15 minutes
when in this position R
you press Start/Stop button C twice when in
this position. The power supply is switched off again if: R
the driver's door is opened and R
you press Start/Stop button C twice when in
this position
Removing the Start/Stop button You can remove the Start/Stop button from the
ignition lock and start the vehicle as normal
using the SmartKey.
It is only possible to switch between Start/Stop
button mode and SmartKey operation when the
transmission is in position P .X
Remove Start/Stop button C from ignition
lock D .
You do not have to remove the Start/Stop but-
ton from the ignition lock when you leave the
vehicle. You should, however, always take the
SmartKey with you when leaving the vehicle. As
long as the SmartKey is in the vehicle: R
the vehicle can be started using the Start/
Stop button R
the electrically powered equipment can be
operated
Starting the engine
Important safety notes
G WARNING
If children are left unsupervised in the vehicle,
they could: R
open the doors, thus endangering other
people or road users. R
get out and disrupt traffic. R
operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they: R
release the parking brake. R
shifting the automatic transmission out of
park position P R
Start the engine.
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 or animals unattended in the146
Driving
Driving and parking

vehicle. Always keep the SmartKey out of
reach of children.
G WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Inhaling
these exhaust gases leads to poisoning. There
is a risk of fatal injury. Therefore never leave
the engine running in enclosed spaces with-
out sufficient ventilation.
G WARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or
parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
General notes During a cold start, the engine runs at higher
speeds to enable the catalytic converter to
reach its operating temperature. The sound of
the engine may change during this time.
Automatic transmission X
Shift the transmission to position P
( Y
page 152).
The transmission position display in the mul-
tifunction display shows P ( Y
page 154).
You can start the engine in transmission posi-
tion P and N .
Starting procedure with the SmartKey To start the engine using the SmartKey instead
of the Start/Stop button, pull the Start/Stop
button out of the ignition lock. X
Turn the SmartKey to position 3 in the ignition
lock and release it as soon as the engine is
running ( Y
page 145). Starting procedure with the Start/Stop
button The Start/Stop button can be used to start the
vehicle manually 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 func-
tion.
You can start the engine if a valid SmartKey is in
the vehicle. Always take the SmartKey with you
when leaving the vehicle, even if you only leave
it for a short time. Pay attention to the important
safety notes. X
Depress the brake pedal and keep it
depressed. X
Press the Start/Stop button once
( Y
page 145).
The engine starts.
Starting procedure via smartphone Observe the important safety notes on starting
the engine ( Y
page 146).
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 SmartKey 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: R
the SmartKey is in the ignition lock R
park position P is selected R
the accelerator pedal is not depressed R
the anti-theft alarm system is not activated Driving 147
Driving and parking Z

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
G WARNING
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.
General notes
C
ECO start/stop display
The ECO start/stop function is activated when-
ever you switch on the engine using the Smart-
Key or the Start/Stop button.
If the engine has been switched off automati-
cally by the ECO start/stop function, the

Problems with the engine Problem
Possible causes/consequences and P 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.
Before attempting to start the engine again: X
Turn the SmartKey back to position Z in the ignition lock.
or X
Press the Start/Stop button repeatedly until all indicator lamps in
the instrument cluster go out. X
Try to start the engine again ( Y
page 146). 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: 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 too weak or
discharged. X
Jump-start the vehicle ( Y
page 335).
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 too high. X
Try to start the engine again.
If the engine still does not start: X
Consult a qualified specialist workshop.
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. X
Only depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic converter
and damage it. X
Have the cause rectified immediately at a qualified specialist work-
shop.
The coolant temperature
gauge 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. X
Stop as soon as possible and allow the engine and the coolant to
cool down. X
Check the coolant level ( Y
page 316). Observe the warning notes
as you do so and add coolant if necessary. Driving 151
Driving and parking Z

Engaging reverse gear R
! Only shift the automatic transmission to R
when the vehicle is stationary. X
If the transmission is in position D or N : push
the DIRECT SELECT lever up past the first
point of resistance. X
If the transmission is in position P : depress
the brake pedal and push the DIRECT SELECT
lever up past the first point of resistance.
The ECO start/stop function is not available
when reverse gear is engaged. Further informa-
tion on the ECO start/stop function
( Y
page 149).
Shifting to neutral N
G WARNING
If children are left unsupervised in the vehicle,
they could: R
open the doors, thus endangering other
people or road users. R
get out and disrupt traffic. R
operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they: R
release the parking brake. R
shifting the automatic transmission out of
park position PR
Start the engine.
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 or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children. X
If the transmission is in position D or R : push
the DIRECT SELECT lever up or down to the
first point of resistance. X
If the transmission is in position P : depress
the brake pedal and push the DIRECT SELECT
lever up or down to the first point of resist-
ance.
If you switch the engine off with the transmis-
sion in position R or D , the automatic transmis-
sion shifts to N automatically. With the SmartKey: if you then open the driv-
er's door or the front-passenger door or remove
the SmartKey from the ignition, the automatic
transmission shifts to P automatically.
With the Start/Stop button: if you t hen open
t
he driver's door or the front-passenger door,
the automatic transmission shifts to P automat-
ically.
If you want the automatic transmission to
remain in neutral N , e.g. when having the vehicle
cleaned in an automatic car wash with a towing
system:
Using the SmartKey: X
Switch on the ignition. X
Depress the brake pedal and keep it
depressed. X
Shift to neutral N . X
Release the brake pedal. X
Release the electric parking brake. X
Switch off the ignition and leave the SmartKey
in the ignition lock.
With the Start/Stop button: X
Remove the Start/Stop button from the igni-
tion lock. X
Insert the SmartKey into the ignition lock. X
Switch on the ignition. X
Depress the brake pedal and keep it
depressed. X
Shift to neutral N . X
Release the brake pedal. X
Release the electric parking brake. X
Switch off the ignition and leave the SmartKey
in the ignition lock.
Engaging drive position D X
If the transmission is in position R or N : push
the DIRECT SELECT lever down past the first
point of resistance. X
If the transmission is in position P : depress
the brake pedal and push the DIRECT SELECT
lever down past the first point of resistance.Automatic transmission 153
Driving and parking Z

If you or others come into contact with fuel,
observe the following: R
Wash away fuel from skin immediately
using soap and water. R
If fuel comes into contact with your eyes,
immediately rinse them thoroughly with
clean water. Seek medical assistance with-
out delay. R
If fuel is swallowed, seek medical assis-
tance without delay. Do not induce vomit-
ing. R
Immediately change out of clothing which
has come into contact with fuel.
G WARNING
Electrostatic buildup can create sparks and
ignite fuel vapors. There is a risk of fire and
explosion.
Always touch the vehicle body before opening
the fuel filler flap or touching the fuel pump
nozzle. Any existing electrostatic buildup is
thereby discharged.
Do not get into the vehicle again during the refu-
eling process. Otherwise, electrostatic charge
could build up again.
! Do not use diesel to refuel vehicles with a
gasoline engine. Do not switch on the ignition
if you accidentally refuel with the wrong fuel.
Otherwise, the fuel will enter the fuel system.
Even small amounts of the wrong fuel could
result in damage to the fuel system and the
engine. Notify a qualified specialist workshop
and have the fuel tank and fuel lines drained
completely.
! Overfilling the fuel tank could damage the
fuel system.
! Take care not to spill any fuel on painted
surfaces. You could otherwise damage the
paintwork.
! Use a filter when adding fuel from a fuel can.
The fuel lines and/or the fuel injection system
could otherwise be blocked by particles from
the fuel can.
If you overfill the fuel tank, fuel could spray out
when the fuel pump nozzle is removed. For further information on fuel and fuel quality
( Y
page 372).
Refueling
General information Pay attention to the important safety notes
( Y
page 159).
Hybrid vehicles: observe the notes on refueling
in the separate operating instructions.
If you unlock/lock the vehicle from the outside,
the fuel filler flap also unlocks/locks.
The position of the fuel filler cap is displayed in
the instrument cluster

Parking
Important safety notes
G WARNING
Flammable material such as leaves, grass or
twigs may ignite if they come into contact with
hot parts of the exhaust system or exhaust
gas flow. There is a risk of fire.
Park the vehicle so that no flammable mate-
rials come into contact with parts of the vehi-
cle which are hot. Take particular care not to
park on dry grassland or harvested grain
fields.
G WARNING
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.
! Always secure the vehicle correctly against
rolling away. Otherwise, the vehicle or its driv-
etrain could be damaged.
To ensure that the vehicle is secured against
rolling away unintentionally: R
the electric parking brake must be applied. R
the transmission must be in position P and the
SmartKey must be removed from the ignition
lock. R
the front wheels must be turned towards the
curb on steep uphill or downhill gradients. R
the empty vehicle must be secured at the
front axle with a wheel chock or similar, for
example, on uphill or downhill gradients. R
a laden vehicle must also be secured at the
rear axle with a wheel chock or similar, for
example, on uphill or downhill gradients. Switching off the engine
G WARNING
The automatic transmission switches to neu-
tral position N when you switch off the engine.
The vehicle may roll away. There is a risk of an
accident.
After switching off the engine, always switch
to parking position P . Prevent the parked vehi-
cle from rolling away by applying the parking
brake. X
Apply the electric parking brake. X
Shift the transmission to position P .X
With the SmartKey: turn the SmartKey to
position 0 in the ignition lock and remove it.
The immobilizer is activated. X
With the Start/Stop button: press the
Start/Stop button ( Y
page 145).
The engine stops and all the indicator lamps in
the instrument cluster go out.
When the driver's door is closed, this corre-
sponds to SmartKey position 1 . When the
driver's door is open, this corresponds to
SmartKey position 0 : "Key removed".
If you switch the engine off with the transmis-
sion in position R or D , the automatic transmis-
sion shifts to N automatically.
With the SmartKey: if you then open the driv-
er's door or the front-passenger door or remove
the SmartKey from the ignition, the automatic
transmission shifts to P automatically.
With the Start/Stop button: if you then open
the driver's door or the front-passenger door,
the automatic transmission shifts to P automat-
ically.
If you want the automatic transmission to
remain in neutral N , e.g. when having the vehicle
cleaned in an automatic car wash with a towing
system: X
Remove the Start/Stop button from the igni-
tion lock. X
Insert the SmartKey into the ignition lock. X
Switch on the ignition. X
Depress the brake pedal and keep it
depressed. X
Shift to neutral N .X
Release the brake pedal.162
Parking
Driving and parking

X
Releas e th e electric parking brake.X
Switc h off th e ignition and leav e th e SmartKey
in th e ignition lock.
The engin e can be switched off in an emergenc y
while th e vehicl e is in motion by pressin g and
holding th e Start/Sto p butto n for three sec -
onds. This function operate s independentl y of
th e ECO start/sto p automatic engin e switch-off
function .
Electric parking brake
General notes
G WARNIN G
If you leav e children unsupervised in th e vehi-
cle , they could set it in motion by, for example: R
release th e parking brake.R
shif t th e automatic transmission out of th e
parking position P .R
start th e engine.
In addition , they may operate vehicl e equip-
men t and become trapped . There is a ris k of
an acciden t and injury.
When leaving th e vehicle, always tak e th e
SmartKey wit h you and loc k th e vehicle. Never
leav e children unsupervised in th e vehicle.
The function of th e electric parking brak e is
dependen t on th e on-board voltage. If th e on -
boar d voltag e is low or there is a malfunction in
th e system, it may no t be possibl e to apply th e
release d parking brake.X
If this is th e case, only park th e vehicl e on
level ground and secure it to preven t it rollin g
away. X
Shift th e automatic transmission to position
P .
It may no t be possibl e to release an applie d
parking brak e if th e on-board voltag e is low or
there is a malfunction in th e system. Contac t a
qualified specialist workshop.
The electric parking brak e performs a function
test at regular intervals while th e engin e is
switched off . The sounds that can be hear d while
this is occurrin g are normal. Applying or releasing manually X
To engage: push handle C .
When th e electric parking brak e is applied,
th e red I (US A only) or $ (Canada
only) indicator lamp lights up in th e instru-
men t cluster.
The electric parking brak e can also be applie d
when th e SmartKey is removed. X
To release: pull handle C .
The red I (US A only) or $ (Canada
only) indicator lamp in th e instrumen t cluste r
goes out .
The electric parking brak e can only be released:R
when th e SmartKey is in position 1 or 2 in th e
ignition loc k ( Y
page 145) or R
if th e ignition was switched on usin g th e
Start/Sto p butto n
Applying automatically The electric parking brak e is automatically
applie d when th e transmission is in position P
and : R
th e engin e is switched off or R
th e driver is no t wearing a seat belt and th e
driver' s door is opened
To preven t th e electric parking brak e from bein g
automatically applied, pull handle C .
The electric parking brak e is also engage d auto -
matically if: R
DISTRONI C PLU S brings th e vehicl e to a
standstill or R
th e HOLD function is keepin g th e vehicl e sta-
tionary R
Active Parking Assis t is keepin g th e vehicl e
stationary Parking 163
Driving and parking Z

In addition, at least one of the following condi-
tions must be fulfilled: R
the engine is switched off R
the driver is not wearing a seat belt and the
driver's door is opened R
there is a system malfunction R
the power supply is insufficient R
the vehicle is stationary for a lengthy period
The red I (USA only) or $ (Canada only)
indicator lamp in the instrument cluster lights
up.
The electric parking brake is not automatically
engaged if the engine is switched off by the ECO
start/stop function.
Releasing automatically The electric parking brake is released automat-
ically when all of the following conditions are
fulfilled: R
the engine is running. R
the transmission is in position D or R .R
the seat belt has been fastened R
you depress the accelerator pedal
If the automatic transmission is in position R ,
the trunk lid must be closed.
If your seat belt is not fastened, the following
conditions must be fulfilled to automatically
release the electric parking brake: R
the driver's door is closed. R
you have shifted out of transmission position
P or you have previously driven faster than
2 mph (3 km/h).
Ensure that you do not depress the accelerator
pedal unintentionally. Otherwise the parking
brake will be released and the vehicle will start
to move.
Emergency braking The vehicle can also be braked during an emer-
gency by using the electric parking brake. X
While driving, push handle C of the electric
parking brake ( Y
page 163).
The vehicle is braked as long as you keep
handle C of the electric parking brake
pressed. The longer electric parking brake
handle C is depressed, the greater the brak-
ing force. During braking: R
a warning tone sounds R
the Please Release Parking Brake mes-
sage appears R
the red I (USA only) or $ (Canada
only) indicator lamp in the instrument cluster
flashes
When the vehicle has been braked to a stand-
still, the electric parking brake is engaged.
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.
Hybrid vehicles: observe the notes on the high-
voltage battery in the separate Operator's Man-
ual.
Driving tips
General driving tips
Important safety notes
G WARNING
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.
G WARNING
If you operate mobile communication equip-
ment while driving, you will be distracted from
traffic conditions. You could also lose control
of the vehicle. There is a risk of an accident.
Only operate this equipment when the vehicle
is stationary.164
Driving tips
Driving and parking

! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately. Drive
on for a short while. This allows the airflow to
cool the brakes more quickly.
Wet roads If you have driven for a long time in heavy rain
without braking, there may be a delayed reac-
tion from the brakes when braking for the first
time. This may also occur after the vehicle has
been washed or driven through deep water.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehicle
washed, brake firmly while paying attention to
the traffic conditions. This will warm up the
brake discs, thereby drying them more quickly
and protecting them against corrosion.
Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt resi-
due may form on the brake discs and brake
pads. This can result in a significantly longer
braking distance. R
In order to prevent any salt build-up, apply the
brakes occasionally while paying attention to
the traffic conditions. R
Carefully depress the brake pedal and the
beginning and end of a journey. R
Maintain a greater distance to the vehicle
ahead.
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 immediately.
Consult a qualified specialist workshop to
arrange this.
! Vehicles with 4MATIC: function or per-
formance tests may only be carried out on a 2-
axle dynamometer. If you wish to operate the
vehicle on such a dynamometer, please con-
sult a qualified specialist workshop in
advance. You could otherwise damage the
drive train or the brake system.
! Vehicles with 4MATIC: the ESP ®
system
operates automatically. The engine and the
ignition must therefore be switched off (the
SmartKey must be in position 0 or 1 in the
ignition lock or the Start/Stop button must be
in position 0 or 1 ) if the electric parking brake
is tested on a brake dynamometer.
Braking triggered automatically by ESP ®
may
cause severe damage to the brake system.
! Vehicles without 4MATIC: the ESP ®
sys-
tem operates automatically. The engine and
the ignition must therefore be switched off
(the SmartKey must be in position 0 or 1 in the
ignition lock or the Start/Stop button must be
in position 0 or 1 ) if: R
the electric parking brake is tested using a
brake dynamometer. R
the vehicle is towed with one axle raised.
Braking triggered automatically by ESP ®
may
cause severe damage to the brake system.
All checks and maintenance work on the brake
system must be carried out at a qualified spe-
cialist 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 functional-
ity of your brakes at regular intervals.
Information on BAS (Brake Assist) ( Y
page 66)
and BAS PLUS (Brake Assist PLUS) ( Y
page 67).
For safety reasons, Mercedes-Benz recom-
mends only installing the following brake disks
and brake pads/linings: R
brake disks that have been approved by
Mercedes-Benz R
brake pads/linings that have been approved
by Mercedes-Benz or that are of an equiva lent
standard of quality
Other brake disks or brake pads/linings can
compromise the safety of your vehicle. Driving tips 167
Driving and parking Z