check engine MERCEDES-BENZ CLS 2017 Owner's Manual

Display messages
Possible causes/consequences and P Solutions
' (USA
only)
M ( Canada
only)
Check Brake Fluid
Level There is no t enough brak e fluid in th e brak e fluid reservoir .
In addition , th e ' (US A only) or M (Canada only) warning lamp
lights up in th e instrumen t cluste r and a warning tone sounds.
G WARNIN G
The braking effec t may be impaired.
There is a ris k of an accident.X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions. Do no t continu e drivin g
under any circumstances. X
Secur e th e vehicl e against rollin g away ( Y
page 141).X
Consult a qualified specialist workshop .X
Do no t add brak e fluid . This does no t correc t th e malfunction .
& Check Brake Pad Wea r The brak e pads/linings hav e reached their wear limit.X
Visit a qualified specialist workshop .
S mbrace Inoperative On e or mor e main features of th e mbrace system are malfunctioning .X
Visit a qualified specialist workshop .
Collision Preven ‐
tio n Assist Plu s
Currently Unavaila‐
ble See Operator' s
Manual COLLISION PREVENTION ASSIST PLU S is temporarily no t operational.
Possibl e causes are: R
th e radar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti c radiation emitted by nearby TV or radi o station s or
other source s of electromagneti c radiationR
th e system is outside th e operating temperature rangeR
th e on-boar d voltag e is to o low.
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
COLLISION PREVENTION ASSIST PLU S is operational again .
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 141).X
Restart th e engine.
Collision Preven ‐
tio n Assist Plu s
Inoperative COLLISION PREVENTION ASSIST PLU S is temporarily inoperative due
to a malfunction . Adaptive Brake Assis t may also hav e failed.X
Visit a qualified specialist workshop .
PRE-SAFE
Inoperative See
Operator' s Manual Importan t function s of PRE-SAF E ®
hav e failed. Al l other occupant
safet y systems , e.g. air bags , remain available.X
Visit a qualified specialist workshop .206
Display messages
On-board computer and displays

Warning/
indicator
lamp Q Signal type
Possible causes/consequences and P Solutions
t
Q Mercedes-AMG vehicles only:
The yellow SPORT handling mode warning lamp is lit while the engine is running.
SPORT handling mode is activated.
G WARNING
When SPORT handling mode is switched on, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident. X
Only switch to SPORT handling mode in accordance with the conditions descri-
bed in the "Activating/deactivating ESP" section ( Y
page 71).
u
Q The red restraint system warning lamp is lit while the engine is running.
The restraint system is malfunctioning.
G WARNING
The air bags or Emergency Tensioning Devices may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
There is an increased risk of injury. X
Observe the additional display messages in the multifunction display. X
Drive on carefully. X
Have the restraint system checked immediately at a qualified specialist work-
shop.
Observe the additional information on restraint systems ( Y
page 41).Warning and indicator lamps in the instrument cluster 231
On-board computer and displays Z

X
Make sure that the windshield wipers are
turned off. X
Pull release lever C on the hood.
The hood is released.
X
Reach into the gap, pull hood catch handle D
up and lift the hood.
If you lift the hood by approximately 15 in
(40 cm), the hood is opened and held open
automatically by the gas-filled strut.
Closing the hood X
Lower the hood and let it fall from a height of
approximately 8 in (20 cm). X
Check that the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Open it again and close it
with a little more force.
Radiator
Do not cover up the radiator, such as with a
thermal mat or insect protection cover. The
readings of the on-board-diagnostic system may
otherwise be inaccurate. Some of these read-
ings are required by law and must be accurate at
all times. Engine oil
Important safety notes
G WARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot.
Working in the engine compartment poses a
risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following.
G WARNING
The engine compartment contains moving
components. Certain components, such as
the radiator fan, may continue to run or start
again suddenly when the ignition is off. There
is a risk of injury.
If you need to do any work inside the engine
compartment: R
switch off the ignition R
never reach into the area where there is a
risk of danger from moving components,
such as the fan rotation area R
remove jewelry and watches R
keep items of clothing and hair, for exam-
ple, away from moving parts
G WARNING
If engine oil comes into contact with hot com-
ponents in the engine compartment, it may
ignite. There is a risk of fire and injury.
Make sure that engine oil is not spilled next to
the filler neck. Let the engine cool down and
thoroughly clean the engine oil off the com-
ponents before starting the engine.
G WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.266
Engine compartment
Maintenance and care

Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
General notes Depending on your driving style, the vehicle
consumes up to 0.8 US qt (0.8 liters) of oil per
600 miles (1,000 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
in a different location.
When checking the oil level: R
park the vehicle on a level surface R
the engine should be switched off for approx-
imately five minutes if the engine is at normal
operating temperature R
if the engine is not at normal operating tem-
perature, e.g. if the engine was only started
briefly, wait about 30 minutes before carrying
out the measurement
Checking the oil level using the oil dip-
stick
Example X
Pull oil dipstick C out of the dipstick guide
tube. X
Wipe off oil dipstick C .X
Slowly slide oil dipstick C into the guide tube
to the stop, and take it out again.
If the level is between MIN mark

Additional service products
Import ant safety notes
G WARNIN G
Certain component s in th e engin e compart-
ment, suc h as th e engine, radiato r and part s
of th e exhaust system, can become ver y hot .
Working in th e engin e compartmen t poses a
ris k of injury.
Wher e possible, let th e engin e cool down and
touch only th e component s described in th e
following.
G WARNIN G
The engin e compartmen t contain s moving
components. Certain components, suc h as
th e radiato r fan , may continu e to run or start
again suddenly when th e ignition is off . There
is a ris k of injury.
If you need to do any wor k inside th e engin e
compartment: R
switch off th e ignitionR
never reac h int o th e area wher e there is a
ris k of danger from moving components,
suc h as th e fan rotation areaR
remove jewelr y and watchesR
keep items of clothing and hair , for exam-
ple, away from moving part s
G WARNIN G
The coolin g system is pressurized, particularly
when th e motor is warm . If you open th e cap ,
you could be scalded if hot coolan t sprays out .
There is a ris k of injury.
Let th e engin e cool down before you open th e
cap . Wear gloves and eye protection . Slowly
open th e cap to reliev e pressure.
G WARNIN G
Opening th e hoo d when th e engin e is over-
heated or when there is a fir e in th e engin e
compartmen t could expos e you to hot gase s
or other servic e products . There is a ris k of
injury. Let an overheate d engin e cool down before
opening th e hood. If there is a fir e in th e
engin e compartment, keep th e hoo d closed
and contact th e fir e department.
Checking coolant level
Exampl e X
Park th e vehicl e on a level surface.
Only chec k th e coolan t level when th e vehicl e
is on a level surfac e and th e engin e has cooled
down . X
Turn th e SmartKey to position 2 in th e ignition
loc k ( Y
page 123).
or X
On vehicles wit h KEYLESS-GO , press th e
Start/Sto p butto n twice ( Y
page 123).X
Chec k th e coolan t temperature display in th e
instrumen t cluster.
The coolan t temperature mus t be belo w
15 8 ‡ (70 †). X
Turn th e SmartKey to position 0 in th e ignition
loc k ( Y
page 123).
or X
Press th e Start/Sto p butto n once on vehicles
wit h KEYLESS-GO ( Y
page 123).X
Slowly tur n cap C half a tur n counter-clock -
wise and allow excess pressur e to escape.X
Turn cap C further counter-clockwise and
remove it .
If th e coolan t is at th e level of marke r bar

i Example: equipment and country-specific
variations possible.
Vehicles with alloy wheels and hub caps On vehicles with alloy wheels and hub caps, a
socket is also provided.
Flat tire
Preparing the vehicle Your vehicle may be equipped with: R
MOExtended tires (tires with run-flat proper-
ties) ( Y
page 278)
Vehicle preparation is not necessary on vehi-
cles with MOExtended tires R
a TIREFIT kit ( Y
page 277)R
an emergency spare wheel ( Y
page 317)
Vehicles equipped with MOExtended tires are
not equipped with a TIREFIT kit at the factory. It
is therefore recommended that you additionally
equip your vehicle with a TIREFIT kit if you mount
tires that do not feature run-flat properties, e.g.
winter tires. A TIREFIT kit may be obtained from
a qualified specialist workshop.
Information on changing and mounting wheels
( Y
page 312). X
Stop the vehicle on solid, non-slippery and
level ground, as far away as possible from
traffic. X
Switch on the hazard warning lamps. X
Secure the vehicle against rolling away
( Y
page 141).X
If possible, bring the front wheels into the
straight-ahead position. X
Vehicles with AIRMATIC: make sure that "nor-
mal" level is selected ( Y
page 159).X
Switch off the engine. X
Remove the SmartKey from the ignition lock.
or, on vehicles with KEYLESS ‑ GO:X
Open the driver's door.
T he vehicle electronics now have status 0 .
This is the same as the SmartKey having been
removed. X
Remove the Start/Stop button from the igni-
tion lock ( Y
page 123).X
Make sure that the passengers are not endan-
gered as they do so. Make sure that no one is
near the danger area while a wheel is being changed. Anyone 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 traffic
conditions when doing so. X
Close the driver's door.
MOExtended tires (tires with run-flat
properties)
General notes With MOExtended tires (tires with run flat char-
acteristics), you can continue to drive your vehi-
cle even if there is a total loss of pressure in one
or more tires. The affected tire must not show
any clearly visible damage.
You can recognize MOExtended tires by the
MOExtended marking which appears on the
sidewall of the tire. You will find this marking
next to the tire size designation, the load-bear-
ing capacity and the speed index ( Y
page 307).
MOExtended tires may only be used in conjunc-
tion with an active tire pressure loss warning
system or with an active tire pressure monitor.
If a pressure loss warning message appears
in the multifunction display: R
observe the instructions in the display mes-
sages ( Y
page 221). R
check the tire for damage. R
if driving on, observe the following notes.
The driving distance possible in run-flat mode is
approximately 50 miles (80 km) when the vehi-
cle is partially laden. When the vehicle is fully
laden it is approximately 19 miles (30 km).
In addition to the vehicle load, the driving dis-
tance possible depends upon: R
Vehicle speed R
Road condition R
Outside temperature
The driving distance p ossible in run-flat mode
may be reduced by extreme driving conditions
or maneuvers, or it can be increased through a
moderate style of driving.
The driving distance possible in run-flat mode is
counted from the moment the tire pressure loss
warning appears in the multifunction display.
You must not exceed a maximum permissible
speed of 50 mph (80 km/h).278
Flat tire
Breakdown assistance

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 jumper cables. 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 skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
plenty of clean water and seek medical atten-
tion.
H Environmental note
Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and recycled to protect the
environment.
Dispose of batteries in an
environmentally friendly
manner. Take discharged
batteries to a qualified spe-
cialist workshop or a special
collection point for used bat-
teries.
! Have the battery checked regularly at a
qualified specialist workshop. Observe the service intervals in the Mainte-
nance Booklet or contact a qualified specialist
workshop for more information.
! Always have work on batteries carried out at
a qualified specialist workshop. Should it, in
exceptional circumstances, be absolutely
necessary to disconnect the 12-volt battery
yourself, observe the following: R
secure the vehicle to prevent it from rolling
away. R
switch off the ignition. R
always disconnect the negative terminal
clamp first, followed by the positive termi-
nal clamp.
After the battery has been disconnected, the
transmission is locked in position P .
After the work has been done, install the bat-
tery and replace the cover of the positive ter-
minal clamp firmly.
Comply with safety precautions and take pro-
tective measures when handling batteries.
Risk of explosion.
Fire, open flames and smoking are
prohibited when handling the bat-
tery. Avoid creating sparks.
Battery acid is caustic. Avoid contact
with skin, eyes or clothing.
Wear suitable protective clothing,
especially gloves, apron and face-
guard.
Rinse any acid spills immediately
with clear water. Contact a physician
if necessary.
Wear eye protection.
Keep children away.
Observe this Operator's Manual.
For safety reasons, Mercedes-Benz recom-
mends that you only use batteries which have
been tested and approved for your vehicle byBattery (vehicle) 283
Breakdown assistance Z

Mercedes-Benz. These batteries provide
increased impact protection to prevent vehicle
occupants from suffering acid burns should the
battery be damaged in the event of an accident.
In order for the battery to achieve the maximum
possible service life, it must always be suffi-
ciently charged.
Like other batteries, the vehicle battery may
discharge over time if you do not use the vehicle.
In this case, have the battery disconnected at a
qualified specialist workshop. You can also
charge the battery with a charger recommended
by Mercedes-Benz. Contact a qualified special-
ist workshop for further information.
Have the battery condition of charge checked
more frequently if you use the vehicle mainly for
short trips or if you leave it standing idle for a
lengthy period. Consult a qualified specialist
workshop if you wish to leave your vehicle
parked for a long period of time.
Remove the SmartKey if you park the vehicle
and do not require any electrical consumers.
The vehicle will then use very little energy, thus
conserving battery power.
If the power supply has been interrupted, e.g. if
you reconnect the battery, you will have to: R
set the clock; see the Digital Operator's Man-
ual
On vehicles with a multimedia system, the
time is set automatically. R
reset the function for folding the exterior mir-
rors in/out automatically, by folding the mir-
rors out once ( Y
page 101).
Charging the battery
! Only use battery chargers with a maximum
charging voltage of 14.8 V.
G WARNING
During charging and jump-starting, explosive
gases can escape from the battery. There is a
risk of an explosion.
Particularly avoid fire, open flames, creating
sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting.
Do not lean over a battery.
G WARNING
Battery acid is caustic. There is a risk of injury. Avoid contact with skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
plenty of clean water and seek medical atten-
tion.
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 charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment ( Y
page 285).X
Open the hood. X
Connect the battery charger to the positive
terminal and ground point in the same order
as when connecting the donor battery in the
jump-starting procedure ( Y
page 285).
Keep away from fire and open flames. Do not
lean over a battery. Never charge the battery if it
is still installed in the vehicle, unless you use a
battery charger which has been tested and
approved by Mercedes-Benz. A battery charger
unit specially adapted for Mercedes-Benz vehi-
cles and tested and approved by Mercedes-
Benz is available as an accessory. It permits the
charging of the battery in its installed position.
Contact an authorized Mercedes-Benz Center
for further information and availability. Read the
battery charger's operating instructions before
charging the battery.
If the warning and indicator lamps do not light up
on the instrument cluster when temperatures
are low, it is probably because the discharged
battery has frozen. In this case, you may neither
charge the battery nor jump-start the vehicle.
The service life of a thawed-out battery may be
shorter. The starting characteristics can be
impaired, particularly at low temperatures. Have
the thawed-out battery checked at a qualified
specialist workshop.284
Battery (vehicle)
Breakdown assistance

Jump-starting For the jump-starting procedure, use only the jump-starting connection point in the engine com-
partment, consisting of a positive terminal and a ground point.
G WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do not inhale any battery gases. Do not lean over the
battery. Keep children away from batteries. Wash away battery acid immediately with plenty of
clean water and seek medical attention.
G WARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk
of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient ven-
tilation while charging and jump-starting. Do not lean over a battery.
G WARNING
During the charging process, a battery produces 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 contact with
vehicle parts. R
Never place metal objects or tools on a battery. R
It is important that you observe the described 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 disconnecting
the jumper cables. R
Never connect or disconnect the battery terminals while the engine is running.
G WARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting 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.
! Avoid repeated and lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
If the indicator and 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 thawed-out battery may be shorter. The starting characteristics can be
impaired, particularly at low temperatures. Have the thawed-out battery checked at a qualified
specialist workshop. Jump-starting 285
Breakdown assistance Z

The fuses are located in various fuse boxes: R
Fuse box in the engine compartment on the
left-hand side of the vehicle, when viewed in
the direction of travel R
Fuse box in the trunk on the right-hand side of
the vehicle, when viewed in the direction of
travel
Fuse box in the engine compartment Pay attention to the important safety notes
( Y
page 290).
G WARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured by
the wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
X
Make sure that the windshield wipers are
turned off. X
Open the hood ( Y
page 265).X
Use a dry cloth to remove any moisture from
the fuse box. X
To open: take lines C out of the guides.X
Move lines C to one side.X
Open retaining clamps D .X
Remove the fuse box cover forwards. X
To close: check whether the seal is lying cor-
rectly in the cover. X
Insert the cover at the rear of the fuse box into
the retainer. X
Fold down the cover and close clamps D .X
Secure lines C in the guides.X
Close the hood. Fuse box in the trunk Pay attention to the important safety notes
( Y
page 290).
X
Open the trunk lid. X
To open: release cover C at the top right and
left-hand sides with a flat object. X
Open cover C downwards in the direction of
the arrow. Fuses 291
Breakdown assistance Z