MERCEDES-BENZ CLS COUPE 2008 Owners Manual

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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Troubleshooting
254 Problem Possible cause/consequence Suggested solutions
The fuel tank has been run com-
pletely dry on a vehicle with a
diesel engine. There is air in the fuel system. X
Refuel the vehicle.
X Switch on the ignition for approximately 10 seconds (key in posi-
tion 2 in the ignition lock).
X Start the engine continuously for up to 40 seconds until it runs
smoothly.
The fuel system is now free of air.
If the engine does not start:
X Wait two minutes.
X Repeat the starting procedure for up to 40 seconds.
If the engine still does not start:
X Consult a qualified specialist workshop. Practical advice
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Troubleshooting
255Engine
Problem Possible cause/consequence Suggested solutions
The engine will not start. HOLD is activated. X
Deactivating HOLD (Y page 145).
X Start the engine again. The engine will not start. You can
hear
the starter motor operating. R
There may be a malfunction in
the engine electronics.
R There may be a malfunction in
the fuel supply. X
Turn the key back to position 0 in the ignition lock before the next
starting attempt.
X Try to start the engine again (Y
page 101). When doing so, remem-
ber that excessively long and frequent attempts to start the engine
will drain the battery.
If the engine does not start after several attempts:
X Consult a qualified specialist workshop. Vehicles with a diesel engine:
The

engine will not start. You can
hear the starter motor operating.
The reserve fuel warning lamp is
on and the fuel gauge shows 0. The fuel tank has been run dry. X
Refuel the vehicle.
X Bleed the fuel system (Y page 254). The engine will not start. You can-
not hear the starter motor oper-
ating. The on-board voltage is too low
because

the starter battery is too
weak or discharged. X
Jump-start the vehicle (Y page 291).
If the engine does not start despite attempting to jump-start it:
X Consult a qualified specialist workshop. Practical advice
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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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Troubleshooting
257Automatic transmission
Problem Possible cause/consequence Suggested solutions
The transmission has problems
shifting gear The transmission is losing oil. X
Have the transmission checked at a qualified specialist workshop
immediately. The acceleration ability is deteri-
orating.
The transmission no longer
changes gear. The transmission is in emergency
mode.
It is only possible to shift into
2nd gear and reverse gear. X
Stop the vehicle.
X Move the selector lever to P.
X Turn the key to position 0 in the ignition lock.
X Wait at least 10 seconds before restarting the engine.
X Move the selector lever to position D or R.
If D
is selected, the transmission shifts into 2nd gear; if R is selec-
ted, the transmission shifts into reverse gear.
X Have the transmission checked at a qualified specialist workshop
immediately. Practical advice
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