2008 MERCEDES-BENZ CLS COUPE warning light

Troubleshooting
241Troubleshooting
Points to remember
G
Risk of accident and injury
Always have maintenance work carried out at a qualified specialist workshop which has the necessary specialist knowledge and tools to
carry out the work required.
Mercedes-Benz recommends that you use a Mercedes-Benz Service Centre for this purpose.
In
particular, work relevant to safety or on safety-related systems must be carried out at a qualified specialist workshop. If this work is not
carried out correctly, the operating safety of your vehicle could be compromised. There is a risk of accident and injury. Indicator and warning lamps in switches and buttons
Problem Possible cause/consequence Suggested solutions
One or all of the indicator lamps
in

the seat ventilation* button are
flashing. There is insufficient voltage
because
too many consumers are
switched on. The seat ventila-
tion* has switched itself off auto-
matically. X
Switch off consumers that are not required, e.g. reading lamps,
interior lighting, etc.
The seat ventilation*
will automatically switch back on as soon as
there is sufficient voltage again. One or all of the indicator lamps
in the seat heating* button are
flashing. There is insufficient voltage
because

too many consumers are
switched on. The seat heating*
has switched itself off automati-
cally. X
Switch off consumers that are not required, e.g. reading lamps,
interior lighting, etc.
The seat heating* will automatically switch back on as soon as
there is sufficient voltage again. Practical advice
* optional
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Troubleshooting
242 Problem Possible cause/consequence Suggested solutions
The steering wheel heating* indi-
cator
lamp on the lower left lever
of the steering column is flashing. There is insufficient voltage
because
too many consumers are
switched on. The steering wheel
heating* has switched itself off
automatically. X
Switch off consumers that are not required, e.g. reading lamps,
interior lighting, etc.
The steering wheel heating*
will automatically switch back on as
soon as there is sufficient voltage again. The indicator lamp in the
2
button on the Thermatic/4-zone
Thermotronic* control panel
flashes three times when you
press

the button. The cooling sys-
tem cannot be switched on. Cooling has been deactivated
due to a malfunction. X
Visit a qualified specialist workshop. The indicator lamp in the
¯
rear-window heating button is
flashing. The rear-window heat-
ing

has switched itself off prema-
turely or cannot be switched on. There is insufficient voltage
because
too many consumers are
switched on. X
Switch off consumers that are not required, e.g. reading lamps,
interior lighting, etc.
The
rear-window heating will automatically switch back on as soon
as there is sufficient voltage again. Vehicles with automatic child
seat recognition on the front-
passenger seat*:
The 5 PASSENGER AIRBAG
OFF warning lamp on the centre
console is lit. A special Mercedes-Benz child
seat with automatic child seat
recognition

has been fitted to the
front-passenger seat. The front-
passenger airbag has therefore
been disabled. Practical advice
* optional
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2007-11-13T09:28:36+01:00 - Seite 242

Troubleshooting
245Problem Possible cause/consequence Suggested solutions
v
The yellow ESP ®
warning
lamp flashes while the
vehicle is in motion. G
Risk of accident
ESP ®
or traction control has
intervened because at least one
wheel has started to spin.
Cruise control or Distronic* is
deactivated. X
Only depress the accelerator pedal as far as necessary when pull-
ing away.
X Release the accelerator pedal while you are driving.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
. Exceptions: (Y page 59).3
The red brake system
warning lamp comes on
while you are driving. You
will also hear a warning
tone. You are driving with the parking
brake applied. X
Release the parking brake.
The warning lamp goes out and the warning tone ceases. 3
The red brake system
warning lamp comes on
while the engine is run-
ning. You will also hear a
warning tone. G
Risk of accident
There is insufficient brake fluid in
the fluid reservoir. X
Do not continue driving under any circumstances.
X Consult a qualified specialist workshop immediately.
X Observe the additional messages in the multi-function display
(Y page 219).
X Under no circumstances should you top up the brake fluid. This will
not rectify the fault. l
The red distance warning
lamp* lights up while the
vehicle is in motion. G
Risk of accident
The distance to the vehicle in
front is too short for the speed
selected. X
Increase the distance. Practical advice
* optional
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2007-11-13T09:28:36+01:00 - Seite 245 Z

Troubleshooting
246 Problem Possible cause/consequence Suggested solutions
l
The red distance warning
lamp* lights up while the
vehicle is in motion. You
will also hear a warning
tone. G
Risk of accident
You are approaching a vehicle in
front at too great a speed or Dis-
tronic*
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. D
The red coolant warning
lamp comes on while the
engine is running. There is insufficient coolant in the
expansion tank.
The coolant is too hot and the
engine is no longer being cooled
sufficiently. X
Stop the vehicle as soon as possible. Pay attention to the traffic
conditions as you do so.
X Allow the engine and coolant to cool.
X Check the coolant level. Observe the warning notes
(Y page 196). Top up the coolant if necessary.
X Have the coolant system checked at a qualified specialist work-
shop if the coolant needs topping up more often than usual. D
The red coolant warning
lamp comes on while the
engine is running. If the coolant level is correct, the
radiator fan may be faulty.
The coolant is too hot and the
engine is no longer being cooled
sufficiently. X
If the coolant temperature is less than 120†, you can continue
driving to the nearest qualified specialist workshop.
X In doing so, avoid heavy loads on the engine (e.g. driving in moun-
tainous terrain) and stop-and-go driving. Practical advice
* optional
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Troubleshooting
248 Problem Possible cause/consequence Suggested solutions
±
The yellow engine diagnos-
tics warning lamp comes
on
while the engine is run-
ning. There may be a malfunction:
R
in the fuel injection system
R in the exhaust system
R in
the ignition system (on vehi-
cles with a petrol engine)
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 spe-
cialist workshop. H
The yellow tyre pressure
monitor* warning lamp is
on. G
Risk of accident
The tyre pressure monitor* has
detected a sudden or significant
pressure loss 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 messages in the multi-function display
(Y page 219).
The warning light will go out after the flat tyre has been changed
and you have been driving for a few minutes. 1
The red SRS warning lamp
is lit while the engine is
running. G
Risk of injury
The restraint systems are faulty.
The airbags or belt tensioners
may either be triggered uninten-
tionally

or, in the event of an acci-
dent, not be triggered at all. X
Visit a qualified specialist workshop immediately. Practical advice
* optional
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2007-11-13T09:28:36+01:00 - Seite 248

Troubleshooting
249Problem Possible cause/consequence Suggested solutions
<
The red seat belt warning
lamp lights up for 6 sec-
onds after the engine
starts up 28
. The seat belt warning lamp
reminds the driver and front
passenger to fasten their seat
belts. X
Fasten your seat belt ( Y page 88).<
After the engine starts you
will
hear a warning tone for
up to 6 seconds 28
. G
Risk of injury
The driver's seat belt is not fas-
tened. X
Fasten your seat belt ( Y page 88).
The warning tone ceases. <
The red seat belt warning
lamp lights up after start-
ing the engine, as soon as
the driver's door or the
front-passenger door is
closed. G
Risk of injury
The driver or front passenger has
not fastened their seat belt. X
Fasten your seat belt ( Y page 88).
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
safely.
The warning lamp goes out. 28
Only for certain countries. Practical advice
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Troubleshooting
251Warning tones
Problem Possible cause/consequence Suggested solutions
The anti-theft alarm system* is
suddenly triggered. You have opened the vehicle
using
the emergency key element
without deactivating the anti-
theft alarm system* first. X
Switch off the alarm (Y page 61). You hear a warning tone. A message appears in the multi-
function display. X
See the explanations for the display message ( Y page 219).You hear a warning tone. You are driving with the parking
brake applied. X
Release the parking brake. You hear a warning tone. You have opened the driver's
door and forgotten to switch off
the lights. X
Turn the light switch to M or U.You hear a warning tone.
G
Risk of injury
The driver or front passenger has
not fastened their seat belt. X
Fasten your seat belt ( Y page 88).You hear a continuous tone. You have switched off the engine
and opened the bonnet or the
driver's

door with Hold activated. X
Deactivate HOLD (Y page 145). Practical advice
* optional
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Troubleshooting
256 Problem Possible cause/consequence Suggested solutions
Vehicles with a petrol engine:
The engine is not running
smoothly and is misfiring. The engine electronics or a
mechanical component of the
engine control unit have been
damaged. X
Only depress the accelerator pedal slightly.
X Have the cause rectified immediately at a qualified specialist work-
shop.
Otherwise,
non-combusted fuel may get into the catalytic converter
and damage it. A coolant temperature of over
120 °C is displayed. The coolant
warning

lamp may also be on and
a warning tone may sound
(Y page 110). The coolant level is too low. The
coolant
is too hot and the engine
is no longer being cooled suffi-
ciently. X
Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level (Y page 196). Observe the warning notes
as you do so and top up the coolant if necessary. If the coolant level is correct, the
radiator fan may be faulty. The
coolant

is too hot and the engine
is no longer being cooled suffi-
ciently. X
If the coolant temperature is less than 120°C, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. when driving on
mountain roads and stop/start driving. Practical advice
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2007-11-13T09:28:36+01:00 - Seite 256