warning light MERCEDES-BENZ CLS COUPE 2011 Service Manual

Display messages Possible causes/consequences and
M Solutions
b
Left revers. lamp
or
Right revers. lamp The lef
torright-hand reversing lamp is faulty.
X Replace the bulb (Y page 104).
or
X Visit a qualified specialist workshop. b
Left daytime driv‐
ing lamp
or
Right
daytime driv‐
ing lamp The left or right-hand daytime driving lamp is defective.
X
Visit a qualified specialist workshop. b
Intell. Light Sys‐
tem inoperative The Intelligent Light System is faulty. The lights remain available
without the Intelligent Light System.
X
Visit a qualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit a qualified specialist workshop. b
AUTO
lights inoper‐
ative The light sensor is faulty.
X
Visit a qualified specialist workshop. b
Switch off lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X
Turn the light switch to c.Adaptive Main-beam
Assist inoperative Adaptive Highbeam Assist is faulty.
X
Visit a qualified specialist workshop. Adaptive Main-beam
Assist currently
unavailable See
Owner's Manual Adaptive Highbeam Assist is deactivated and temporarily inoper-
ative if:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
X Clean the windscreen.
Adaptive Highbeam Assist is available again if:
R the dirt (e.g .slush) drops away while the vehicle is in motion.
R the system detects that the camera is fully operational again.
The Adaptive Main-beam Assist available again message
is displayed. Display messages
223On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Radar sensor
deactivated autom.
See Owner's Manual Vehicles with a navigation system: the vehicle is close to a radio
telescope facility and is therefore prohibited from transmitting any
rada
rsignals .The radar sensor system has switched off automat-
ically.
DISTRONIC PLUS (Y page 154) is switched off automatically if it
is activated. Awarning tone also sounds.
If Blind Spot Assist (Y page 183) or Active Blind Spot Assist
(Y page 186) are activated, they are switched off automatically.
The yellow 9indicator lamps also light up in the exterior mir-
rors.
BAS PLUS (Brake Assist PLUS) (Y page 57) and the
PRE-SAFE ®
Brake (Y page 61) are also no tavailable.
X Drive on.
These functions are available again as soon as the vehicle is far
enough away from the radio telescope facility (Y page 327).Lane Keeping
Assist currently
unavailable. see
Owner's Manual
or
Active Lane Keep‐
ing Assist cur‐
rently unavailable
see Owner's Manual Lane Keeping Assist or Active Lane Keeping Assist is deactivated
and temporarily inoperative if:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the lane markings are worn, dark or covered, for example by dirt
or snow.
Lane Keeping Assist or Active Lane Keeping Assist is operational
again and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the camera is fully operational again.
If the display message continues to be displayed:
X Clean the windscreen. Lane Keeping
Assist inoperative
or
Active Lane Keep‐
ing Assist inoper‐
ative Lane Keeping Assist or Active Lane Keeping Assist is faulty.
X
Visi taqualified specialist workshop. 228
Display messagesOn-board computer and displays

Warning and indicator lamps in the instrument cluster
Brakes
Problem Possible causes/consequences and
M Solutions
J
The yellow brake sys-
tem warning lamp
lights up while the
engine is running.
G
Risk of accident
The brake syste mis malfunctioning and the braking characteris-
tics may be affected.
X If the multifunction display shows a display message, please
observe this.
X Drive on carefully.
X Visit a qualified specialist workshop. J
The red brake system
warning lamp comes on
while the vehicle is
moving. A warning tone
also sounds.
You are driving with the parking brake applied.
X
Release the parking brake
The warning lamp goes out and the warning tone ceases. J
The red brake system
warning lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
G
Risk of accident
The brake boosting effect is malfunctioning and the braking char-
acteristics may be affected.
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 Apply the parking brake.
X Consult a qualified 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. A warning tone
also sounds.
G
Risk of accident
There is not enough brake fluid in the brake fluid reservoir.
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 Apply the parking brake.
X Consult a qualified specialist workshop immediately.
X Observe the additional display messages in the multifunction
display.
Do not top up the brake fluid. This does not correct the error. 238
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Seat belt
Problem Possible causes/consequences and
M Solutions
7
The red seat belt warn-
ing lamp lights up for
six seconds after the
engine starts
35
. The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.
X
Fasten your seat belt (Y page 42).7
After starting the
engine, the red seat
belt warning lamp lights
up. In addition, a warn-
ing tone sounds for up
to
6s econds. 35 G
Risk of injury
The driver's seat belt is not fastened.
X Fasten your seat belt (Y page 42).
The warning tone ceases. 7
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.
G
Risk of injury
The driver or fron tpassenger has no tfastened their seat belt.
X Faste nyour seat belt (Y page 42).
The warning lamp goes out. G
Risk of injury
There are objects on the front-passenger seat.
X Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out. 35
Only for certain countries. Warning and indicator lamps in the instrument cluster
239On-board computer and displays Z

Safety systems
Problem Possible causes/consequences and
M Solutions
!
The yellow ABS warning
lamp is lit while the
engine is running.
G
Risk of accident
ABS (Anti-lock Brake System) has been deactivated due to a fault.
For this reason, BAS (Brake Assist), BAS PLUS, ESP ®
(Electronic
Stability Program), EBD (Electronic Brake force Distribution),
PRE-SAFE ®
,P RE-SAFE ®
Brake, the HOLD function, hill start assist
and adaptive brake ligh tare also deactivated, for example.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visi taqualified specialist workshop. !
The yellow ABSw
arning
lamp is lit while the
engine is running. G
Ris
kofa ccident
AB Sis temporarily unavailable. Therefore, BAS, BAS PLUS, ESP ®
,
EBD, PRE-SAFE ®
, PRE-SAFE ®
Brake, the HOLD function, hill start
assist and the adaptive brake lights, for example, are also deacti-
vated.
Self diagnosis is not yet complete.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements, at a speed above 20 km/h.
The functions mentioned above are available againw hen the
warning lamp goes out.
If the warning lamp is still on:
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
241On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
֌!
The yellow ESP
®
and
ESP ®
OFF warning
lamps and the yellow
ABS warning lamp are
lit while the engine is
running. A warning tone
also sounds. G
Risk of accident
EBD is faulty. Therefore, ABS,B AS, BAS PLUS, ESP®
, PRE-SAFE ®
,
PRE-SAFE ®
Brake, the HOLD function, hill start assist and the
adaptive brake lights, for example, are not available either.
The brake system continue sto function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. J֌!
The red brake warning
lamp, the yellow ESP
®
and ESP ®
OFF warning
lamps and the yellow
ABS warning lamp are
lit while the engine is
running. G
Risk of accident
ABS and ESP ®
are faulty. Therefore, BAS, BAS PLUS, EBD,
PRE-SAFE ®
,P RE-SAFE ®
Brake, the HOLD function, hill start assist
and the adaptive brake lights, for example, are no tavailable either
due to a malfunction.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visi taqualified specialist workshop. ÷
The yellow ESP
®
warn-
ing lamp flashes while
the vehicle is in motion. G
Risk of accident
ESP ®
or traction control has intervened because ther eis a risk of
skidding or at least one wheel has started to spin.
Cruise control or DISTRONIC PLUS is deactivated.
X Only depress the accelerator pedal as far as necessary when
pulling away.
X Release the accelerator pedal while the vehicle is in motion.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
.
Exceptions: (Y page 58).242
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
M Solutions
å
The yellow ESP
®
OFF
warning lamp is lit while
the engine is running. G
Risk of accident
ESP ®
is deactivated. ESP ®
will not stabilise the vehicle if it starts
to skid or if a wheel starts to spin.
X Reactivate ESP ®
.
Exceptions: (Y page 58).
X Adapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. M
AMG vehicles only:
The yellow SPORT han-
dling mode warning
lamp is lit while the
engine is running.
G
Risk of accident
SPORT handling mode is activated. ESP ®
only stabilises the vehi-
cle in extreme situations. ESP ®
intervention may not be able to
provide sufficient assistance in such situations and the vehicle
may start to skid.
X Reactivate ESP ®
.
Exceptions: (Y page 58).
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. ֌
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. G
Risk of accident
ESP ®
, BAS, BAS PLUS, PRE-SAFE ®
, PRE-SAFE ®
Brake, the HOLD
function, hill start assist and the adaptive brake lights are not
available due to a malfunction .ESP ®
will not stabilise the vehicle
if it starts to skid or if a wheel starts to spin.
The brake system continues to function normally, bu twithout the
functions listed above.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. 6
The red SRS warning
lamp is lit while the
engine is running.
G
Risk of injury
The restraint systems are malfunctioning. The airbags or belt ten-
sioners may either be triggered unintentionally or, in the even tof
an accident, no tbe triggered at all.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. Warning and indicator lamps in the instrument cluster
243On-board computer and displays Z

Engine
Problem Possible causes/consequences and
M Solutions
;
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 the fuel system
The emission limit values may be exceeded and the engin emay
be running in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop. ;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running.
Vehicles with a diesel engine: the fuel tan
khas been run dry
(Y page 146).
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 no tbe
checked. 8
The yellow reserve 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 when 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
star
toft he 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
Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
X Apply the parking brake.
X Consult a qualified specialist workshop. 244
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Driving systems
Problem Possible causes/consequences and
M Solutions
·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.
G
Risk of accident
The distance to the vehicle in fron tis too small for the speed
selected.
X Increase the distance. ·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.
Aw arning tone also
sounds. G
Ris
kofa ccident
Aw arning is issued if:
R you are approaching a vehicle in fron tattoo great a speed
R DISTRONIC PLUS or PRE-SAFE ®
Brake has detected a stationary
obstacle in your line of travel
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action. Tyres
Problem Possible causes/consequences and
M Solutions
h
The yellow tyre pres-
sure monitor warning
lamp is on. G
Risk of accident
The tyre pressure monitor has detected a loss of pressure in at
least one of the tyres.
X Stop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditions as you do
so.
X Observe the additional display messages in the multifunction
display.
X Check the tyre pressure. If necessary, correc tthe tyre pressure
(Y page 307).
X If necessary, change a wheel (Y page 309).246
Warning and indicator lamps in the instrument clusterOn-board computer and displays

vehicle to a haltb
y braking carefully. Do not
make any sudden steering movements when
doing so.
Information on tyre pressures is displayed in
the multifunction display. Afte rafew minutes
of driving, the current tyre pressure of each
tyre is show ninthe multifunction display.
i The tyre pressure values indicated by the
on-board computer may differ from those
measured at a filling station with a pressure
gauge. The tyre pressures shown by the on-
board computer refer to those measured at
sea level. At high altitudes, the tyre pres-
sure values indicated by a pressure gauge
are higher than those shown by the on-
board computer. In this case, do not reduce
the tyre pressures.
i The operation of the tyre pressure moni-
tor can be affected by interference from
radio transmitting equipment (e.g. radio
headphones, two-way radios) that may be
being operated in or near the vehicle.
Checking tyre pressure electronically X
Make sure that the key is in posi-
tion 2(Ypage 129) in the ignition lock.
X Use the =or; button on the steer-
ing wheel to select the Service menu.
X Use the 9or: button to select
Tyre pressure .
X Press the abutton.
The current tyre pressure for each wheel
will be displayed in the multifunction dis-
play.
If the vehicle has been parked for longer than
20 minutes, you will see the Tyre pressure
displayed after a few minutes of
driving message.
After a teach-in period, the tyre pressure
monitor automatically recognises new
wheels or new sensors. As long as a clear
allocation of the tyre pressure values to the
individual wheels is not possible, the Tyrepressure monitor active message isshown instead of the tyre pressure display.
The tyre pressures are already being moni-
tored.
i
If a spare wheel/emergency spare wheel
is fitted, for a few minutes the system may
continue to show the tyre pressure of the
wheel that has been removed. If this
occurs, note that the value displayed for
the position where the spare tyre is fitted
is not the same as the spare wheel/emer-
gency spare wheel's current tyre pressure.
Tyre pressure monitor warning mes-
sages If the tyre pressure monitor detects a signifi-
cant pressure loss on one or more tyres, a
warning message is shown in the multifunc-
tion display.
Awarning tone also sounds and
the tyre pressure warning lamp lights up in
the instrument cluster.
Each tyre that is affected by a significant loss
of pressure is highlighted with a colour.
If the Please correct tyre pressure(s) message appears in the multifunction dis-
play:
X
Chec kthe tyre pressure on all four wheels
and correct it if necessary.
i If the wheel positions on the vehicle are
interchanged, the tyre pressures may be
displayed for the wrong positions for a
short time. This is rectified after a few
minutes of driving, and the tyre pressures
are displayed for the correct positions.
Restarting the tyre pressure monitor When you restart the tyre pressure monitor,
all existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tyre pressures as the refer-
ence values for monitoring. In most cases, the
tyre pressure monitor will automatically
detect the new referencev alues after you
have changed the tyre pressure. 308
Tyre pressureWheels and tyres