2008 MERCEDES-BENZ CLS COUPE Owners Manual

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
247Problem Possible cause/consequence Suggested solutions
D
The red coolant warning
lamp comes on while the
engine is running. You will
also hear a warning tone. The coolant level is too low.
The coolant temperature has
exceeded 120 †. The engine is
not being cooled sufficiently and
may be damaged. 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. You will
also hear a warning tone. If the coolant level is correct, the
radiator fan may be faulty.
The coolant temperature has
exceeded 120 †. The engine is
not being cooled sufficiently and
may be damaged. X
Do not continue driving under any circumstances.
X Consult a qualified specialist workshop. ±
The yellow engine diagnos-
tics warning lamp comes
on
while the engine is run-
ning. Vehicles with a diesel engine: the
fuel tank has run dry. X
Start the engine three to four times after refuelling.
Emergency running mode is cancelled. The vehicle need not be
checked. Practical advice
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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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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
250 Problem Possible cause/consequence Suggested solutions
<
The red seat belt warning
lamp
flashes and you hear
an intermittent warning
tone. G
Risk of injury
The driver or front passenger has
not fastened their seat belt and
you are driving faster than
25 km/h

or have driven faster
than 25 km/h for a short time. X
Fasten your seat belt ( Y page 88).
The warning lamp goes out and the intermittent warning tone
ceases. G
Risk of injury
There are objects on the front-
passenger seat and you are driv-
ing faster than 25 km/h

or have
driven faster than 25 km/h for a
short time. X
Remove the objects from the front-passenger seat and stow them
safely.
The warning lamp goes out and the intermittent warning tone
ceases. W
The yellow reserve fuel
warning lamp comes on
while the engine is run-
ning. The fuel level has fallen below the
reserve range. The operation of
the

auxiliary heating* can no lon-
ger be guaranteed. X
Refuel at the nearest filling station. Practical advice
* optional
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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
252 Accident
Problem Possible cause/consequence Suggested solutions
Fuel is leaking from the vehicle.
G
Risk of fire
The fuel line or the fuel tank has
been damaged. X
Switch off the ignition immediately.
X Remove the ignition key.
X Do not restart the engine under any circumstances.
The leaking fuel creates a risk of fire or explosion.
X Consult a qualified specialist workshop. You are unable to determine the
extent of the damage. X
Consult a qualified specialist workshop. You cannot detect any damage. X
Start the engine as normal. The NECK-PRO head restraints
on the driver's and front-
passenger seats have been trig-
gered. Your vehicle has been involved in
a rear-end collision. X
Reset the NECK-PRO head restraints (Y page 269). Practical advice
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Troubleshooting
253Fuel and fuel tank
Problem Possible cause/consequence Suggested solutions
Fuel is leaking from the vehicle.
G
Risk of fire
The fuel line or the fuel tank is
defective. X
Turn the key to position 0 in the ignition lock immediately and
remove it.
X Do not restart the engine under any circumstances.
The leaking fuel creates a risk of fire or explosion.
X Consult a qualified specialist workshop. The fuel filler flap cannot be
opened. The fuel filler flap is not released. X
Unlock the vehicle (Y page 266). The opening mechanism is jam-
med. X
Consult a qualified specialist workshop. Practical advice
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