engine MERCEDES-BENZ CLS 2018 Service Manual

the vehicle. This occurs, for example, when
starting the engine.
To start the vehicle without actively using the
SmartKey: R
the Start/Stop button must be inserted in the
ignition lock. R
the SmartKey must be in the vehicle. R
the vehicle must not be locked with the
SmartKey or KEYLESS-GO ( Y
page 76).
Do not keep the KEYLESS-GO key: R
with electronic devices, e.g. a mobile phone
or another SmartKey. R
with metallic objects, e.g. coins or metal foil. R
inside metallic objects, e.g. a metal case.
This can affect the functionality of KEYLESS-GO.
If you lock the vehicle with the SmartKey's
remote control or with KEYLESS-GO, after a
short time: R
you will not be able to switch on the ignition
with the Start/Stop button. R
you will not be able to start the engine with the
Start/Stop button until the vehicle is
unlocked again.
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 KEYLESS-GO
C
Start/Stop button
D
Ignition lock
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up. Indicator and warning lamps, see
( Y
page 226). 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.
If you press Start/Stop button C once when
in this position, the ignition is deactivated
again.
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
vehi cle. 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.124
Driving
Dr ivi ng an d parking

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.
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
i The catalytic converter is preheated for up
to 30 seconds after a cold start. The sound of
the engine may change during this time.
Automatic transmission X
Shift the transmission to position P .
The transmission position display in the mul-
tifunction display shows P .
i You can start the engine in transmission
position P and N . Starting procedure with the SmartKey
i To start the engine using the SmartKey
instead of KEYLESS-GO, pull the Start/Stop
button out of the ignition lock. X
Turn the SmartKey to position 3 in the ignition
lock ( Y
page 123 )a nd release it as soon as the
engine is running.
Using KEYLESS-GO to start the engine
i 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 auto-
matic engine start function. X
Depress the brake pedal and keep it
depressed. X
Press the Start/Stop button once
( Y
page 123).
The engine starts.
Pulling away
General notes
G WARNING
If the engine speed is above the idling speed
and you engage transmission position D or R ,
the vehicle could pull away suddenly. There is
a risk of an accident.
When engaging transmission position D or R ,
always firmly depress the brake pedal and do
not simultaneously accelerate.
! If a warning tone sounds and the Release
Park. Brake message appears in the multi-
function display, the parking brake is still
applied. Release the parking brake.
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 ( Y
page 199).Driving 125
Driving an d parking Z

It is only possible to shift the transmission from
position P to the desired position if you depress
the brake pedal. If the brake pedal is not
depressed, the DIRECT SELECT lever can still be
moved but the parking lock remains engaged.
i Upshifts take place at higher engine speeds
after a cold start. This helps the catalytic con-
verter to reach its operating temperature
more quickly.
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.
G WARNING
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: R
you are pulling away on a level road or on a
downhill gradient. R
the transmission is in position N .R
the parking brake is applied. R
ESP ®
is malfunctioning.
ECO start/stop function
Introduction 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
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
you start the engine.
If the engine has been switched off automati-
cally by the ECO start/stop function, the

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
i All of the vehicle's systems remain active
when the engine is stopped automatically.
i The HOLD function can also be activated if
the engine has been switched off automati-
cally. It is then not necessary to continue
applying the brakes during the automatic stop
phase. When you depress the accelerator
pedal, the engine starts automatically and the
braking effect of the HOLD function is deac-
tivated.
Automatic engine switch-off can take place a
maximum of four times in a row (initial stop, then
three subsequent stops).
Mercedes-AMG vehicles: the number of con-
secutive automatic engine switch-offs is unlimi-
ted.
All other models: automatic engine switch-off
can take place a maximum of four times in a row
(initial switch-off, then three subsequent switch-
offs).
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 RR
you move the transmission out of position PR
you switch to drive program S , S+ or M
(Mercedes-AMG vehicles) R
you unfasten your seat belt or open the driv-
er'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 i Shifting the transmission to position P does
not start the engine.
Deactivating or activating the ECO
start/stop function Mercedes-AMG vehicles X
To deactivate: in drive program C , press ECO
button C .
or X
Switch to drive program S , S+ or M
( Y
page 134).
Indicator lamp D goes out.X
To activate: press ECO button C .
Indicator lamp D lights up.
If drive program S , S+ or M is active, the auto-
matic transmission switches to drive program
C .
If indicator lamp D is off, the ECO start/stop
function has been deactivated manually or as
the result of a malfunction. The engine will then
not be switched off automatically when the vehi-
cle stops.
All other models Driving 127
Dr ivi ng an d parking Z

X
To deactivate: press ECO button C .
Indicator lamp D goes out.X
To activate: press ECO button C .
Indicator lamp D lights up.
If indicator lamp D is off, the ECO start/stop
function has been deactivated manually or as the result of a malfunction. The engine will then
not be switched off automatically when the vehi-
cle stops.
Problems with the engine Problem
Possible causes/consequences and P Solutions
The engine does not
start. The HOLD function or DISTRONIC PLUS is activated. X
Deactivate the HOLD function ( Y
page 157) or DISTRONIC PLUS
( Y
page 155). X
Try to start the engine again.
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 0 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 124). 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 285).
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
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.128
Driving
Driving an d parking

Problem
Possible causes/consequences and P Solutions
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 268). Observe the warning notes
as you do so and add coolant if necessary.
Automatic transmission
Important safety notes
G WARNING
If the engine speed is above the idling speed
and you engage transmission position D or R ,
the vehicle could pull away suddenly. There is
a risk of an accident.
When engaging transmission position D or R ,
always firmly depress the brake pedal and do
not simultaneously accelerate.
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. Selector lever (Mercedes-AMG vehi-
cles)
Overview of transmission positions
]
Park position with parking lock ^
Reverse gear \\
Neutral [
Drive
Transmission position and drive pro-
gram display The current transmission position and drive pro-
gram appear in the multifunction display.Automatic transmission 129
Driving and parking Z

Engaging park position P
! If the engine speed is too high or the vehicle
is moving, do not shift the automatic trans-
mission directly from D to R , from R to D or
directly to P . The automatic transmission
could otherwise be damaged. X
Push the DIRECT SELECT lever in the direction
of arrow P .
Transmission position display P is shown in
the multifunction display.
Depressing the brake and pushing the DIRECT
SELECT lever up or down disengages the park-
ing lock. The transmission is in N neutral.
In order to shift from park position P directly into
R or D :R
depress the brake pedal and R
push the DIRECT SELECT lever up or down
past the first point of resistance
Engaging park position P automatically Park position P is automatically engaged if:R
you switch off the engine using the Smartkey
and remove the SmartKey R
you switch off the engine using the Smartkey
or using the Start/Stop button and open the
driver's door or front-passenger door R
the driver's door is opened when the vehicle is
stationary or driving at very low speed and the
transmission is in position D or R
Under certain conditions, the automatic trans-
mission shifts automatically to transmission
position P if the HOLD function or DISTRONIC
PLUS is activated. Observe the information on
the HOLD function ( Y
page 158) and on
DISTRONIC PLUS ( Y
page 153).
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 126).
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 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 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 KEYLESS-GO: if you then open the driver's
or f r
ont-passenger door, the automatic trans-
mission shifts to P .
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:Automatic transmission 131
Driving and parking Z

X
Vehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock. X
Insert the Smartkey into the ignition lock. X
All vehicles: switch the ignition on.X
Depress the brake pedal and keep it
depressed. X
Shift to neutral N .X
Release the brake pedal. X
Release the 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. Transmission positions E Park position
Only shift the transmission into posi-
tion P when the vehicle is stationary
( Y
page 142). The parking lock
should not be used as a brake when
parking. Always apply the parking
brake in addition to the parking lock
in order to secure the vehicle.
If the vehicle electronics are malfunc-
tioning, the transmission may be
locked in position P . Have the vehicle
electronics checked immediately at a
qualified specialist workshop.
Park position P is automatically
engaged if: R
you switch off the engine using the
SmartKey and remove the Smart-
Key R
you switch off the engine using the
SmartKey or using the Start/Stop
button and open the driver's door
or front-passenger door R
the driver's door is opened when
the vehicle is stationary or driving
at very low speed and the trans-
mission is in position D or R
F Reverse gear
Only shift the transmission into posi-
tion R when the vehicle is stationary.132
Automatic transmission
Driving and parking

D Neutral
Do not shift the transmission to N
while driving. Otherwise, the auto-
matic transmission could be dam-
aged.
No power is transmitted from the
engine to the drive wheels.
Releasing the brakes will allow you to
move the vehicle freely, e.g. to push
it or tow it.
If ESP ®
is deactivated or faulty: shift
the transmission only to position N if
the vehicle is in danger of skidding,
e.g. on icy roads.
If you switch the engine off with the
transmission in position R or D , the
automatic transmission shifts to N
automatically.
! Rolling in neutral N can damage
the drive train.
: Drive
The automatic transmission changes
gear automatically. All forward gears
are available.
Driving tips
Changing gear The automatic transmission shifts to the indi-
vidual gears automatically when it is in trans-
mission position D . This automatic gear shifting
behavior is determined by: R
the selected drive program R
the position of the accelerator pedal R
the road speed
Accelerator pedal position Your style of driving influences how the auto-
matic transmission shifts gear: R
little throttle: early upshifts R
more throttle: late upshifts
Mercedes-AMG vehicles
When shifting down, the double-clutch function
is active regardless of the currently selected
drive program. The double-clutch function reduces load change reactions and is conducive
to a sporty driving style. The sound generated by
the double-clutch function depends on the drive
program selected.
Kickdown Use kickdown for maximum acceleration: X
Depress the accelerator pedal beyond the
pressure point.
The automatic transmission shifts to a lower
gear depending on the engine speed. X
Ease off the accelerator pedal once the
desired speed is reached.
The automatic transmission shifts back up.
Rocking the vehicle free Rocking the vehicle free by shifting back and
forth between transmission positions D and R
can help to free a vehicle that has become stuck
in mud or snow. The vehicle's engine manage-
ment restricts switching between transmission
positions D and R to speeds up to a maximum of
5 mph (9 km/h). To shift back and forth between
transmission positions D and R , move the
DIRECT SELECT lever up and down past the
point of resistance.
Program selector button
General notes
All vehicles (except Mercedes-AMG vehicles and
vehicles with AMG sports package) X
Press program selector button C repeatedly
until the letter for the desired drive program
appears in the multifunction display.Automatic transmission 133
Driving an d parking Z

Vehicles with the AMG Sports package X
Press program selector button C repeatedly
until the letter for the desired drive program
appears in the multifunction display.
The program selector button allows you to
choose between different driving characteris-
tics.
i Further information about permanent drive
program M ( Y
page 136).
As well as this permanent drive program M ,
you can also activate temporary drive pro-
gram M ( Y
page 135).
E Economy Comfortable, economical
driving
S Sport Sporty driving style
M Manual Manual gear shifting
i For further information on the automatic
drive program, see ( Y
page 135).
i The automatic transmission shifts to auto-
matic drive program E each time the engine is
started. Mercedes-AMG vehicles
Drive program selector with manual drive program X
Turn drive program selector C until the
desired drive program appears in the multi-
function display in the speedometer.
The drive program indicator on drive program
selector C lights up in red.
i Further information about permanent drive
program M ( Y
page 136).
As well as this permanent drive program M ,
you can also activate temporary drive pro-
gram M ( Y
page 135).
C Controlled
Efficiency Comfortable, economical
driving
S Sport Sporty driving style
S+ SportPlus Particularly sporty driving
style
M Manual Manual gear shifting
RS RACE
START Optimal vehicle accelera-
tion from a standstill
i For further information on the automatic
drive program, see ( Y
page 135).
i The automatic transmission shifts to auto-
matic drive program C each time the engine is
started.
i RS cannot be selected during normal driv-
ing. For further information on RACE START,
see ( Y
page 158).134
Automatic transmission
Driving and parking