ECU MERCEDES-BENZ CLS COUPE 2012 Service Manual

Vehicle
Display messages Possible causes/consequences and
M Solutions
To start engine,
shift to either P
or N Yo
uh avea ttempte dtostart the engine with the transmission in
position Ror D.
X Shift the transmission to position Por N. Auxiliary battery
malfunction The auxiliary battery for the automatic transmission is no longer
being charged.
X
Visit aquali fied specialist workshop. Apply brake to
deselect
Par
k(P) position Yo
uh avea ttempte dtomove the transmission selector lever to
position D,Ror Nwithou tdepressing the brake pedal.
X Depress the brake pedal. Risk of vehicle
rolling
Transmission not
in P The driver's door is open and the transmission is in position
R,N
or D.
Aw arning tone also sounds.
X Shift th etransmission to position P.
X Secure th evehicle against rolling away ( Ypage 159). Withou
tchanging gear,
consul
tworkshop You canno
tchange the transmission position due to amalfunction.
Aw arning tone also sounds.
If transmission position Dis selected:
X Drive to aqualified specialist worksho pwithout shiftin gthe
transmission from position D.
If transmission position R,Nor Pis selected:
X Consult aqualified specialist workshop. Onl
ys elect position
Pwhen vehicle is station‐
ary The vehicle is moving.
X
Pull ove rand stop the vehicl esafelyass oonasp ossible,p aying
attention to road and traffic conditions.
X Shift the transmission to position P.N The boot lid is open.
X
Close the boot lid. 254
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
M The bonne
tisopen. Awarning tone also sounds.
G WARNING
The open bonne tmay then bloc kyour view when the vehicle is in
motion.
There is arisk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 159).
X Close the bonnet. C At least one door is open.
Awarning tone also sounds.
X Close all doors. _
Rea
rl efts eat backrest not
locked or
Rear right sea
tback‐ res
tn ot locked The backres
tinthe rear is not engaged on the left-hand and/or
right-hand side. Awarning tone also sounds.
X Push th ebackres tback until it engages. _
Front lef
tseat backrest not
locked or
Front right sea
tback‐ res
tn ot locked The driver'
sorfront-pa ssenger seat backres tisnot engaged. A
warning tone also sounds.
X Push the backrest back until it engages. &
inoperative Bat‐
tery low The on-board voltage is too low. The auxiliary heating has switched
itself off or cannot be switched on (Y
page 132).
X Drive for alonger distance.
The battery is being charged. The auxiliary heating is operational
againass oon as the on-board electrical system voltage is suf-
ficient. &
inoperative
Refuel
vehicle There is too little fuel in the fuel tank. The auxiliary heating cannot
be switched on (Y
page 132).
X Refuel at the nearest filling station. Display messages
255On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Â
Change key batter‐
ies The batterie
softheKEYLESS-GO ke yare discharged.
X Change th ebatterie s(Ypage 79). Â
Key not detected
(re
dd isplay message) The KEYLESS-GO ke
yisnotin th evehicle.
Aw arning tone also sounds.
If th eengineiss witched off ,you can no longer loc kthe vehicle
centrally or start the engine.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 159).
X Locate the KEYLESS-GO key. The KEYLESS-GO key is not detected while the engine is running
because there is interference from
astrongs ource of radio waves.
Aw arning tone also sounds.
X Pull ove rand stop the vehicl esafelyass oonasp ossible,p aying
attention to road and traffic conditions.
X Secure the vehicle against rolling away( Ypage 159).
X Operate the vehicle with the key in the ignition lock if necessary. Â
Key not detected
(white displaym
es-
sage) The KEYLESS-GO key cannot be detected at present.
X
Change the location of the key with the KEYLESS-GO functions
in the vehicle.
If the KEYLESS-GO key is still not detected:
X Operate the vehicle with the key in the ignition lock if necessary. Â
Key still in vehi‐
cle The KEYLESS-GO key has been detected inside the vehicle during
locking.
X
Remove the KEYLESS-GO key from the vehicle. Display messages
257On-board computer and displays Z

Safety
Seat belts Problem Possible causes/consequences and
M Solutions
ü
Only for certain coun-
tries: the red seat belt
warning lamp lights up
for six seconds after
the engine starts.
The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.
X
Fasten your seat belt (Y page 49).ü
Only for certain coun-
tries: the red seat belt
warning lamp lights up
after the engine starts.
In addition,
awarning
tone sounds for up to
six seconds. The driver's seat belt is not fastened.
X
Fasten your seat belt (Y page 49).
The warning tone ceases. ü
The red seat belt warn-
ing lamp lights up after
the engine starts, as
soon as the driver's or
the front-passenger
door is closed.
The driver or front passenger has not fastened their seat belt.
X
Fasten your seat belt (Y page 49).
The warning lamp goes out. There are objectsont
he front-passenger seat.
X Remove the objectsf rom the front-passenger seat and stow
them in asecure place.
The warning lamp goes out. ü
The red seat belt warn-
ing lamp flashes and an
intermittenta
udible
warning sounds. The driver or passenger has no
tfastened their seat belt .Atthe
same time, the car is being driven faster than 25 km/h or has been
briefly driven faster than 25 km/h.
X Fasten your seat belt (Y page 49).
The warning lamp goes out and the intermittent warning tone
ceases. There are objectsont
he front-passenger seat. At the same time,
you are driving faster than 25 km/h or have briefly driven faster
than 25 km/h.
X Remove the objectsf rom the front-passenger seat and stow
them in asecure place.
The warning lamp goes out and the intermittent warning tone
ceases. Warning and indicator lampsint
he instrument cluster
259On-board computer and displays Z

Safety systems
Problem Possible causes/consequences and
M Solutions
J
The yellow brake sys-
tem warning lamp
lights up while the
engine is running.
G
WARNING
The brake system is malfunctioning and the braking characteris-
tics may be affected.
There is arisk of an accident.
X If the multifunction display shows adisplay message, please
observe this.
X Drive on carefully.
X Visit aqualified specialist workshop. J
The red brake system
warning lamp comes on
while the engine is run-
ning.
Awarning tone
also sounds. G
WARNING
The brake boosting effect is malfunctioning and the braking char-
acteristic smay be affected.
There is arisk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away (Y page 159).
X Consult aqualified specialist workshop.
X Observe the additional display messages in the multifunction
display. J
The red brake system
warning lamp comes on
while the engine is run-
ning.
Awarning tone
also sounds. There is insufficient brake fluid in the brake fluid reservoir.
G WARNING
The braking efficienc ymay be impaired.
There is arisk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away (Y page 159).
X Do not top up the brake fluid. Topping up will not rectify the
fault.
X Consult aqualified specialist workshop.
X Observe the additional display messages in the multifunction
display. 260
Warning and indicator lampsint
he instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
M Solutions
8
The yellowr
eserve fuel
warning lamp lights up
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 against rolling away (Y page 159).
X Consult aqualified specialist workshop. Warning and indicator lampsint
he instrument cluster
267On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
?
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 mal-
functioning.
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 against rolling away (Y page 159).
X Leave the vehicle and keep asafe 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 299).
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
under 120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine 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.
Awarning 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 compartmen ttocatch fire.
Steam from an overheated engine can cause serious burns, which
can occur just by opening the bonnet.
This poses arisk 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 against rolling away (Y page 159).268
Warning and indicator lampsint
he instrument clusterOn-board computer and displays

Tyres
Problem Possible causes/consequence
sand M Solutions
h
The yellow tyr
epres-
sure monitor warning
lamp is on. The tyr
epressure monitor ha sdetecte dalossofp ressure in at
leas tone of the tyres.
G WARNING
With tyr epressures which ar etoo low, ther eisariskoft he fol-
lowing hazards:
R the tyres may burst, especiallyast he load and vehicle speed
increase.
R the tyres may wear excessively and/or unevenly, which may
greatly impair tyre traction.
R the driving characteristics, as well as steering and braking, may
be greatly impaired.
There is arisk of an accident.
X Stop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditionsasy ou do
so.
X Secure the vehicle against rolling away (Y page 159).
X Observe the additional displaym essages in the multifunction
display.
X If there is aflat tyre, inspect the tyres (Y page 312).
X Check the tyre pressure (Y page 334).
X If necessary, correct the tyre pressure. 270
Warning and indicator lampsint
he instrument clusterOn-board computer and displays

Useful information
i This Owner's Manual describes all mod-
els, series and optional equipment for your
vehicle that were available at the time of
going to press. National variation sare pos-
sible. Not ethat your vehicle may not be
equipped with all of the function sdescri-
bed. This is also the case for system sand
function srelevan ttosafety.
i Read the information on qualified special-
ist workshops: (Y page 23). Stowage areas
Loading guidelines
G
WARNING
Secure and position the load as described in
the loading guidelines.
Otherwise, vehicle occupants could
be injured by the load being thrown around in
the even tofsharp braking, asudden change
in direction or an accident.
You will find further information in the "Secur-
ing aload" section.
Even if you follow all the loading guidelines,
the load will increase the risk of injury in the
event of an accident. G
WARNING
Keep the boot lid closed while the vehicle is
in operation. Otherwise, you could be pois-
oned by exhaust fumes enteringt he vehicle.
The handling characteristics of aladen vehi-
cle are dependent on the distribution of the
load within the vehicle. For this reason, you
should observe the following notes when
transporting aload:
R when transporting aload, never exceed the
maximum permissible gross vehicle weight or the permissible axle loads for the vehicle
(including occupants).
R position heavy loads as far forwards as pos-
sible and as low down in the boot as pos-
sible.
R the load must not protrude above the upper
edge of the seat backrests.
R always place the load against the rear or
front seat backrests. Make sure that the
seat backrests are securely locked into
place.
R always place the load behind unoccupied
seats if possible.
R secure the load with sufficiently stronga nd
wear-resistant lashing material. pad sharp
edges for protection.
i Load restraintsa re available at any quali-
fied specialist workshop, e.g. aMercedes-
Benz Service Centre. Stowage compartments
Important safety notes G
WARNING
The stowage compartments must be closed
when items are stored in them. Luggage nets
are not designed to secure heavy items of
luggage.
You or other vehicle occupants could be
injured by objectsb eing thrown around if you:
R brake sharply
R change direction suddenly
R are involved in an accident
Sharp-edged and fragile objectsm ust not be
placed in the luggagen et.
Do not place hard objectsint he map pockets.
Objectsm ust not protrude from the map
pockets. 272
Stowage areasStowing and features

Stowage compartments in the rear
centre console
X
To open: slide covers :and ;in the
direction of the arrow.
i There is a12Vpower socket in the front
stowage compartment.
Stowage compartment in the rear seat
armrest X
To open: fold down seat armrest ;.
X Fold cover :of the armrest upwards. Stowage nets
G
WARNING
Only place lightweight items in the luggage
net. Do not use it to transport heavy, bulky,
sharp-edged or fragile objects. In the event of
an accident, the luggage net will not secure
the transported goods. Luggage nets are located in the front-
passenger footwell and on the left and right-
hand sides of the boot. Through-loading facility in the rear
bench seat
Important safety notes G
WARNING
Do not carry heavy or hard objectsi nside the
vehicle or in the boot unless they are secured.
Otherwise, you and other vehicle occupants
could be injured by objectsb eing thrown
around the vehicle in the event of sharp brak-
ing, asudden change in direction or an acci-
dent. G
WARNING
Always drive with the boot lid closed. Exhaust
fumes could otherwise enter the vehicle inte-
rior.
The left-hand and right-hand rear seat backr-
ests can be folded down separately to
increase the boot capacity.
Folding the seat backrest forwards i
Vehicles with memory function :when you
fold one or both parts of the rear seat back-
rest forwards, the respective front seat
moves forward slightly, when necessary, in
order to avoid contact. Stowage areas
275Stowing and features Z