check engine MERCEDES-BENZ CLS COUPE 2014 Owner's Guide

Engine
Problem
Possible causes/consequences and
M
MSolutions ;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running. There may be a fault, for example:
R in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system (for vehicles with petrol engines)
R in the fuel system
The emission limit values may be exceeded and the engine may be running in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop. Vehicles with a diesel engine: the fuel tank has been run dry
(Y
page 180).
X Start the engine three to four times after refuelling.
If the yellow engine diagnostics warning lamp goes out, emer-
gency running mode is cancelled. The vehicle need not be
checked. 8
The yellow reserve fuel
warning lamp is on
while the engine is run-
ning.
The fuel level has dropped into the reserve range.
Operation of the auxiliary heating is deactivated if the fuel level
drops into the reserve range.
X Refuel at the nearest filling station. ?
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gauge is at the start of the scale. The temperature sensor for the coolant temperature gauge is
faulty.
The coolant temperature is no longer being monitored. There is a risk of engine damage if the coolant temperature is too high.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine. Do not continue driving
under any circumstances.
X Secure the vehicle to prevent it from rolling away (Y page 180).
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
295On-board computer and displays Z

Problem
Possible causes/consequences and
M
MSolutions ?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may
be blocked or the electric engine radiator fan may be malfunc-
tioning.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
X Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle to prevent it from rolling away (Y page 180).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant, observing the
warning notes (Y page 331).
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Do not start the engine again until the coolant temperature is
below 120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid putting the engine under heavy load as you do so, e.g.
driving in mountainous terrain and stop-start traffic. ?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
The coolant temperature has exceeded 120 †. The airflow to the
engine radiator may be blocked or the coolant level may be too
low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Never drive with an overheated engine. Driving when your engine is overheated can cause some fluids which may have leaked into
the engine compartment to catch fire.
In addition, steam from an overheated engine can cause serious
burns, which can occur just by opening the bonnet.
There is a risk of injury.
X Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle to prevent it from rolling away (Y page 180).296
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem
Possible causes/consequences and
M
MSolutions X
Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant, observing the
warning notes (Y page 331).
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X If the coolant temperature is below 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid putting the engine under heavy load as you do so, e.g.
driving in mountainous terrain and stop-start traffic. Driving systems
Problem
Possible causes/consequences and
M MSolutions ·
The red distance warn-
ing lamp lights up while
the vehicle is in motion. The distance to the vehicle in front is too small for the speed
selected.
X Increase the distance. ·
The red distance warn-
ing lamp lights up while
the vehicle is in motion. A warning tone also
sounds. You are approaching a vehicle or a stationary obstacle in your line
of travel at too high a speed.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.
Further information on PRE‑SAFE ®
Brake (Y page 76). Warning and indicator lamps in the instrument cluster
297On-board computer and displays Z

!
Make sure that the windscreen wipers are
not folded away from the windscreen. Oth-
erwise, you could damage the windscreen
wipers or the bonnet. X
Make sure that the windscreen wipers are
switched off.
X Pull release lever :on the bonnet.
The bonnet is released. X
Reach into the gap, pull bonnet catch han-
dle ;up and lift the bonnet.
If you lift the bonnet by approximately
40 cm, the bonnet is opened and held open automatically by the gas-filled strut.
Closing the bonnet X
Lower the bonnet and let it fall from a
height of approximately 20 cm.
X Check that the bonnet has engaged prop-
erly.
If the bonnet can be raised slightly, it is not
properly engaged. Open it again and close
it with a little more force. Radiator
Vehicles with a diesel engine: do not cover
the radiator. Do not use thermal mats, insect
protection covers or anything similar. Doing
so can cause the Onboard Diagnostics Sys-
tem to display inaccurate values. Some of
these values are legally required and must
always be correct. Engine oil
General notes Depending on your driving style, the vehicle
consumes up to 0.8 litres of oil per 1000 km.
The oil consumption may be higher than this
when the vehicle is new or if you frequently
drive at high engine speeds.
Depending on the engine, the oil dipstick may be installed at a different location.
When checking the oil level:
R park the vehicle on a level surface
R the engine should be switched off for
approximately five minutes if the engine is
at normal operating temperature
R if the engine is not at normal operating
temperature, e.g. if the engine was only
started briefly, wait approximately
30 minutes before carrying out the meas-
urement
Checking the oil level using the oil dip-
stick G
WARNING
Certain components in the engine compart-
ment could be very hot, e.g. the engine, the
radiator and parts of the exhaust system.
There is a risk of injury when accessing the
engine compartment.
As far as possible, allow the engine to cool
down and only touch the components descri- bed in the following. Engine compartment
329Maintenance and care Z

Example: engine oil filler cap
X Turn cap :anti-clockwise and remove it.
X Top up the engine oil.
If the oil level is at or below the MIN mark on
the oil dipstick, top up with 1.0 lof engine
oil.
X Replace cap :on the filler neck and turn
clockwise.
Make sure that the cap locks securely into place.
X Check the oil level again with the oil dip-
stick (Y page 329).
For further information on engine oil, see
(Y page 404). Other service products
Checking the coolant level G
WARNING
Certain components in the engine compart-
ment could be very hot, e.g. the engine, the
radiator and parts of the exhaust system.
There is a risk of injury when accessing the
engine compartment.
As far as possible, allow the engine to cool
down and only touch the components descri- bed in the following. G
WARNING
The engine cooling system is under pressure, particularly if the engine is warm. You could
be scalded by hot coolant spraying out when
opening the cap. There is a danger of injury. Allow the engine to cool before opening the
cap. Wear gloves and protective eyewear
when opening. Slowly turn the cap half a turn
to allow pressure to escape. X
Park the vehicle on a level surface.
Only check the coolant level if the vehicle is
on a level surface and the engine has
cooled down.
X Turn the key to position 2in the ignition
lock (Y page 159).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 159).
X Check the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
70 †.
X Turn the key to position 0in the ignition
lock (Y page 159).
X Slowly turn cap :half a turn anti-clock-
wise to allow excess pressure to escape.
X Turn cap :further anti-clockwise and
remove it.
If the coolant is at the level of marker bar =
in the filler neck when cold, there is enough coolant in coolant expansion tank ;.
If the coolant level is approximately 1.5 cm above marker bar =in the filler neck when
warm, there is enough coolant in coolant
expansion tank ;.
X If necessary, top up with coolant that has
been tested and approved by Mercedes-
Benz.
X Replace cap :and turn it clockwise as far
as it will go. Engine compartment
331Maintenance and care Z

Maintaining the time-dependent service
schedule:
X Note down the service due date displayed
in the multifunction display before discon-
necting the battery.
or X After reconnecting the battery, subtract
the battery disconnection periods from the service date shown on the display.
Hiding service messages X
Press the aor% button on the steer-
ing wheel.
Displaying service messages X
Switch the ignition on.
X Press the =or; button on the steer-
ing wheel to select the Service
Service menu.
X Press the 9or: button to select the
ASSYST PLUS
ASSYST PLUS submenu and confirm by
pressing the abutton.
The service due date appears in the multi-
function display.
Information about Service Resetting the ASSYST PLUS service inter-
val display
! If the ASSYST PLUS service interval dis-
play has been inadvertently reset, this set-
ting can be corrected at a qualified special-
ist workshop.
Have service work carried out as described in the Service Booklet. This may otherwise
lead to increased wear and damage to the
major assemblies or the vehicle.
A qualified specialist workshop, e.g. a
Mercedes-Benz Service Centre, will reset the ASSYST PLUS service interval display after
the service work has been carried out. You
can also obtain further information on main-
tenance work, for example. Special service requirements
The prescribed service interval is based on
normal operation of the vehicle. Service work
will need to be performed more often if the
vehicle is operated under arduous conditions or increased loads, for example:
R regular city driving with frequent intermedi-
ate stops
R if the vehicle is primarily used to travel
short distances
R for frequent operation in mountainous ter-
rain or on poor road surfaces
R if the engine is often left idling for long peri-
ods
In these or similar operating conditions, have,
for example, the air filter, engine oil and oil
filter changed more frequently. The tyres
must be checked more frequently if the vehi-
cle is operated under increased loads. Fur-
ther information can be obtained at a quali-
fied specialist workshop, e.g. a Mercedes-
Benz Service Centre.
Driving abroad
An extensive Mercedes-Benz Service network is also available in other countries. You can
obtain further information from any
Mercedes-Benz Service Centre. AdBlue
®
service indicator
i For BlueTEC vehicles only.
To function properly, BlueTEC exhaust gas
aftertreatment must be operated with the
reducing agent AdBlue ®
. AdBlue ®
is topped
up as part of the service. Under normal oper-
ating conditions, a full tank of AdBlue ®
should
last until the next service due date.
Depending on how and where the vehicle is
used, there may be an increase in the
AdBlue ®
consumption, resulting in the next
service due date being brought forward.
Certain display messages show that AdBlue ®
must be topped up, e.g.: Service
333Maintenance and care Z

Refill AdBlue at workshop See Own‐
Refill AdBlue at workshop See Own‐
er's Manual
er's Manual
Refill AdBlue at workshop No start Refill AdBlue at workshop No start
in .. km
in .. km
A warning signal also sounds.
You can no longer start the engine when the
AdBlue ®
supply has been used up
(Y page 273).
! Have the AdBlue ®
tank topped up at a
qualified specialist workshop only. The
vehicle may otherwise be damaged or
soiled.
Before taking a trip with your vehicle outside
Europe, have the AdBlue ®
supply checked at
a qualified specialist workshop. If necessary,
have AdBlue ®
topped up. Before a prolonged
stay outside of Europe, consult a qualified
specialist workshop.
Observe the notes on AdBlue ®
(Y page 403).
Further information about BlueTEC exhaust
gas aftertreatment and AdBlue ®
can be
obtained at a qualified specialist workshop,
e.g. a Mercedes-Benz Service Centre. Care
General notes
H
Environmental note
Dispose of empty packaging and cleaning
cloths in an environmentally responsible man-
ner.
! For cleaning your vehicle, do not use any
of the following:
R dry, rough or hard cloths
R abrasive cleaning agents
R solvents
R cleaning agents containing solvents
Do not scrub.
Do not touch the surfaces or protective
films with hard objects, e.g. a ring or ice
scraper. You could otherwise scratch or
damage the surfaces and protective film. !
Do not park up the vehicle for an extended
period straight after cleaning it, particularly after having cleaned the wheels with wheel
cleaner. Wheel cleaners could cause
increased corrosion of the brake discs and
brake pads/linings. For this reason, you
should drive for a few minutes after clean-
ing. Braking heats the brake discs and the
brake pads/linings, thus drying them. The
vehicle can then be parked up.
Regular care of your vehicle is a condition for
retaining the quality in the long term.
Use care products and cleaning agents rec-
ommended and approved by Mercedes-Benz. Washing the vehicle and cleaning the
paintwork
Automatic car wash G
WARNING
Braking efficiency is reduced after the vehicle has been washed. There is a risk of an acci-
dent.
After washing the vehicle, brake carefully
while paying attention to the traffic conditions in order to restore full braking efficiency.
! 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
! Make sure that:
R the side windows and sliding sunroof are
closed completely.
R the blower for the ventilation/heating is
switched off (OFF button is depressed).
R the windscreen wiper switch is at posi-
tion 0.
The vehicle could otherwise be damaged. 334
CareMaintenance and care

Flat tyre
Preparing the vehicle
Your vehicle may be equipped with: R MOExtended tyres (tyres with run-flat char-
acteristics) (Y page 347)
Vehicle preparation is not necessary on
vehicles with MOExtended tyres.
R a TIREFIT kit (Y page 345)
R an emergency spare wheel (only for certain
countries) (Y page 390)
Information on changing/fitting a wheel
(Y page 373).
X Stop the vehicle as far away as possible
from traffic on solid, non-slippery and level
ground.
X Switch on the hazard warning lamps.
X Secure the vehicle against rolling away
(Y page 180).
X If possible, bring the front wheels into the
straight-ahead position.
X Vehicles with AIRMATIC: make sure that
"normal" level is selected (Y page 202).
X Switch off the engine.
X Vehicles without KEYLESS-GO: remove
the key from the ignition lock.
X Vehicles with KEYLESS-GO: open the
driver's door.
The on-board electronics now have status
0 . This is the same as the key having been
removed.
X Vehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock
(Y page 159).
X All occupants must get out of the vehicle.
Make sure that they are not endangered as they do so.
X Make sure that no one is near the danger
area while a wheel is being changed. Any-
one who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.
X Get out of the vehicle. Pay attention to traf-
fic conditions when doing so. X
Close the driver's door.
X Place the warning triangle a suitable dis-
tance away (Y page 344). Observe legal
requirements. MOExtended tyres (tyres with run-flat
characteristics)
General notes With MOExtended tyres (tyres with run-flat
characteristics), you can continue to drive
your vehicle even if there is a total loss of
pressure in one or more tyres. The affected
tyre must not show any clearly visible dam-
age.
You can recognise MOExtended tyres by the
MOExtended marking which appears on the
tyre wall. You will find this marking next to the
tyre size designation, the load-bearing capa-
city and the speed index.
MOExtended tyres may only be used in con-
junction with an active tyre pressure loss
warning system or tyre pressure monitoring
system.
If the pressure loss warning message
appears in the multifunction display:
R observe the instructions in the display mes-
sages (Y page 280).
R check the tyre for damage.
R if driving on, observe the following notes.
The maximum driving distance is approx-
imately 80 km when the vehicle is partially
laden and approximately 30 km when the
vehicle is fully laden.
In addition to the vehicle load, the driving dis- tance possible depends upon:
R speed
R road condition
R outside temperature
The driving distance possible in run-flat mode may be reduced by extreme driving condi-
tions/manoeuvres, or it can be increased
through a moderate style of driving. Flat tyre
347Breakdown assistance

Before handling the battery, touch the vehicle
body to remove any existing electrostatic
build-up.
The highly flammable gas mixture is created
while the battery is charging and when jump- starting.
Always make sure that neither you nor the
battery is electrostatically charged. Electro-
static charge is created, for example:
R by wearing synthetic fibre clothing
R due to friction between clothing and the
seat
R when you pull or push the battery across
carpet or other synthetic materials
R when you rub the battery with a cloth G
WARNING
During the charging process, a battery produ- ces hydrogen gas. If a short circuit occurs or
sparks are created, the hydrogen gas can
ignite. There is a risk of an explosion.
R Make sure that the positive terminal of a
connected battery does not come into con- tact with vehicle parts.
R Never place metal objects or tools on a bat-
tery.
R It is important that you observe the descri-
bed order of the battery terminals when
connecting and disconnecting a battery.
R When jump-starting, make sure that the
battery poles with identical polarity are
connected.
R It is particularly important to observe the
described order when connecting and dis-
connecting the jump leads.
R Never connect or disconnect the battery
terminals while the engine is running. G
WARNING
Battery acid is caustic. There is a risk of injury. Avoid contact with the skin, eyes or clothing.
Do not inhale any battery gases. Do not lean
over the battery. Keep children away from batteries. Wash battery acid immediately with
water and seek medical attention. H
Environmental note Batteries contain pollutants.
It is illegal to dispose of them
with the household rubbish.
They must be collected sep-
arately and disposed of in anenvironmentally responsible
recycling system. Dispose of batteries in an
environmentally responsible
manner. Take discharged
batteries to a qualified spe-
cialist workshop or to a col-
lection point for used batter-
ies.
! Have the battery checked regularly at a
qualified specialist workshop.
Observe the service intervals in the Service
Booklet or contact a qualified specialist
workshop for more information.
! You should have all work involving the
battery carried out at a qualified specialist
workshop. In the exceptional case that it is
necessary for you to disconnect the battery yourself, make sure that:
R you switch off the engine and remove the
key. On vehicles with KEYLESS-GO,
ensure that the ignition is switched off.
Check that all the indicator lamps in the
instrument cluster are off. Otherwise,
electronic components, such as the
alternator, may be damaged.
R you first remove the negative terminal
clamp and then the positive terminal
clamp. Never swap the terminal clamps.
Otherwise, the vehicle's electronic sys-
tem may be damaged.
R the transmission is locked in position P
after disconnecting the battery. The vehi-
cle is secured against rolling away. You
can then no longer move the vehicle. 352
Battery (vehicle)Breakdown assistance

batteries. Wash battery acid immediately with
water and seek medical attention. G
WARNING
A discharged battery can freeze at tempera-
tures below freezing point. When jump-start-
ing the vehicle or charging the battery, gases can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a maxi-
mum charging voltage of 14.8 V.
! Only charge the battery using the jump-
start connection point.
The jump-starting connection point is in the
engine compartment (Y page 355).
X Open the bonnet.
X Connect the battery charger to the positive
terminal and earth point in the same order
as when connecting the donor battery in
the jump-starting procedure (Y page 355).
If the indicator/warning lamps do not light up at low temperatures, it is very likely that the
discharged battery has frozen. In this case,
you may neither charge the battery nor jump-
start the vehicle. The service life of a battery
that has been thawed may be reduced. The
starting characteristics may be impaired,
especially at low temperatures. Have the
thawed battery checked at a qualified spe-
cialist workshop.
Never charge a battery still installed in the
vehicle unless a battery charger unit
approved by Mercedes-Benz is being used . A battery charger unit specially adapted for
Mercedes-Benz vehicles and tested and
approved by Mercedes-Benz is available as an
accessory. It permits the charging of the bat- tery in its installed position. Contact a
Mercedes-Benz Service Centre for informa-
tion and availability. Read the battery charg-
er's operating instructions before charging
the battery. 354
Battery (vehicle)Breakdown assistance