2016 MERCEDES-BENZ CLS check engine light

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 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 128). 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 294).
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.
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 276). Observe the warning notes
as you do so and add coolant if necessary. Driving 133
Driving and parking Z

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: as the ESP ®
sys-
tem operates automatically, the engine and
the ignition must be switched off (SmartKey in
position 0 or 1 in the ignition lock or Start/
Stop button in position 0 or 1 ) while the park-
ing brake is being tested on a brake dyna-
mometer.
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake sys-
tem.
! Vehicles with 4MATIC: as the ESP ®
sys-
tem operates automatically, the engine and
the ignition system must be switched off
(SmartKey in position 0 or 1 in the ignition
lock or Start/Stop button in position 0 or 1 )
when: R
testing the parking brake on a brake dyna-
mometer. R
you intend to have the vehicle towed with
one of the axles raised.
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake sys-
tem.
All checks and maintenance work on the brake
system must be carried out at a qualified spe-
cialist worksho p.
Ha ve 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. To do so,
press firmly on the brake pedal when driving at a
high speed. This improves the grip of the brake
pads.
You can find a description of Brake Assist (BAS)
on ( Y
page 65) or of BAS PLUS on ( Y
page 65).
The braking characteristics of the vehicle can be
seriously impaired if: R
brake pads other than those recommended
are installed R
the recommended brake fluid is not used
Safe braking can no longer be guaranteed.
AMG high-performance and ceramic
brakes
The high-performance brake system is only
installed on the Mercedes-AMG
CLS 63 S 4MATIC model. Driving tips 151
Driving and parking Z

Display messages
Possible causes/consequences and P Solutions
' (USA
only)
M ( Canada
only)
Check Brake Fluid
Level There is no t enough brak e flui d 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 146).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 radiation .R
th e system is outside th e operating temperature range.R
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 146).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 .Display messages 21 5
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.
Engine oil
General notes
Depending on your driving style, the vehicle
consumes up to 0.9 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
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.
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

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. Information on setting the clock
can be found in the Digital Operator's Manual
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 104)
Charging the battery
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 use battery chargers with a maximum
charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment ( Y
page 294).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 294).
If the indicator/warning lamps do not light up at
low temperatures, it is very likely that the dis-
charged battery has frozen. In this case, you
may neither charge the battery nor jump-start
the vehicle. The service life of a thawed-out bat-
tery may be shorter. The starting characteristics
may be impaired, especially at low tempera-
tures. Have the thawed-out battery checked at a
qualified specialist workshop.
Never charge a battery still installed in the vehi-
cle unless a battery charger unit approved by
Mercedes-Benz is being used . 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.Battery (vehicle) 293
Breakdown assistance Z

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, at low temperatures, the indicator lamps/warning lamps in the instrument cluster do not light up,
it is highly 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.294
Jump-starting
Breakdown assistance