2008 MERCEDES-BENZ CLS COUPE Owners Manual

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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Troubleshooting
258 Parktronic*
Problem Possible cause/consequence Suggested solutions
Only the red segments in the
Parktronic
warning display are lit.
You also hear a warning tone for
approximately two seconds.
Parktronic is deactivated after
approximately 20 seconds and
the indicator lamp in the Park-
tronic button lights up. Parktronic has malfunctioned
and has switched itself off. X
If problems persist, have Parktronic checked at a qualified spe-
cialist workshop. Only the red segments in the
Parktronic

warning display are lit.
Parktronic is deactivated after
approximately 20 seconds. The Parktronic sensors are dirty
or there is interference. X
Clean the Parktronic sensors ( Y page 214).
X Switch the ignition back on. Only the red segments in the
Parktronic

warning display are lit.
Parktronic is deactivated after
approximately 20 seconds. The problem may be caused by an
external source of radio or ultra-
sound waves. X
See if Parktronic functions in a different location. Practical advice
* optional
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Troubleshooting
259Headlamps and turn signals
Problem Possible cause/consequence Suggested solutions
The headlamps or the turn signals
in
the exterior mirrors are misted
up on the inside. Air humidity is very high. X
Drive with the headlamps switched on.
The headlamps are demisted after a short distance. The headlamp housing is not
sealed and moisture has been
able to enter. X
Have the headlamps checked at a qualified specialist workshop. Windscreen wipers
Problem Possible cause/consequence Suggested solutions
The windscreen wipers are jam-
med. Leaves or snow, for example, may
be obstructing the windscreen
wiper movement. The wiper
motor has been deactivated. X
For safety reasons, you should remove the key from the ignition
lock.
X Remove the cause of the obstruction.
X Switch the windscreen wipers back on. The windscreen wipers fail com-
pletely. The windscreen wiper drive is
malfunctioning. X
Select another wiper speed on the combination switch.
X Have the windscreen wipers checked at a qualified specialist work-
shop. Practical advice
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Troubleshooting
260 Windows
Problem Possible cause/consequence Suggested solutions
A side window will not close. An object is blocking the side win-
dow and preventing it from clos-
ing. X
Remove the object(s).
X Close the side window. You cannot see the cause. X
Close the side window with increased force or without the anti-
entrapment feature ( Y page 99).Mirrors
Problem Possible cause/consequence Suggested solutions
An exterior mirror has been
pushed out of position. Vehicles with exterior mirrors that cannot be folded in/out electri-
cally:
X
Push the mirror into the correct position manually.
Vehicles with electrically folding exterior mirrors*:
X Press the mirror-folding button* ( Y page 84) repeatedly until you
hear a distinct click.
The
mirror housing is engaged again and you can adjust the mirror
as usual (Y page 84). Practical advice
* optional
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Troubleshooting
261Key
Problem Possible cause/consequence Suggested solutions
You cannot lock or unlock the
vehicle using the key. The key batteries are discharged
or nearly discharged. X
Point the tip of the key at the driver's door handle from close range
and try to open the vehicle again.
If this does not work:
X Lock or unlock the vehicle using the emergency key element
(Y page 266).
X Check the key batteries (Y page 270) and replace them if neces-
sary ( Y page 270). The key is faulty. X
Lock or unlock the vehicle using the emergency key element
(Y page 266).
X Have the key checked at a qualified specialist workshop. The battery charge indicator lamp
of the key does not go on during
the test. The key batteries are discharged. X
Change the batteries ( Y page 270).You have lost a key. X
Have the key cancelled at a Mercedes-Benz Service Centre.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the manual locks changed too. You have lost the emergency key
element. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the manual locks changed too. Practical advice
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