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Problem
Possible causes/consequences and
X XSolutions The NECK-PRO head
restraints on the driv-
er's and the front-pas-
senger's seats have
been triggered. Your vehicle has been involved in a rear-end collision.
X
Reset the NECK-PRO head restraints (Y page 215).Fuel and fuel tank
Problem
Possible causes/consequences and
X XSolutions Fuel is leaking from the
vehicle.
G
Risk of explosion or fire
The fuel line or the fuel tank is defective.
X Turn the key to position 0(Y page 61) in the ignition lock imme-
diately and remove it.
X Do not restart the engine under any circumstances.
X Consult a qualified specialist workshop. The fuel filler flap can-
not be opened. The fuel filler flap is not released.
or
The key batteries are discharged.
X
Unlock the vehicle using the emergency key element
(Y page 213).
X Open the tailgate (Y page 60).
X Manually unlock the fuel filler flap via the emergency release
(Y page 215). The fuel filler flap is released, but the opening mechanism is jam-
med.
X
Release the fuel filler flap by hand (Y page 215).
X Consult a qualified specialist workshop. 206 TroubleshootingPractical advice
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Problem
Possible causes/consequences and
X
X Solutions The fuel tank in a diesel
engine vehicle has
been run completely
dry and the engine will
not start. There is air in the fuel system.
X Fill the fuel tank (min. 5 litres).
X Turn the ignition on for at least 10 seconds. Turn the key to
position 2(Y page 61) in the ignition lock.
X Start the engine continuously for up to 10 seconds until it runs
smoothly.
If the engine does not start:
X Turn the ignition on again for at least 10 seconds. Turn the key
to position 2(Y page 61) in the ignition lock.
X Start the engine again continuously for up to 10 seconds until
it runs smoothly.
If the engine still won't start after three attempts:
X Consult a qualified specialist workshop. Engine
Problem
Possible causes/consequences and
X
X Solutions The engine will not
start. You can hear the
starter motor operat-
ing. R
There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.
R The on-board voltage is too low because the starter battery is
too weak or discharged.
X Turn the key back to position 0(Y page 61)in the ignition lock
before the next starting attempt.
X Try to start the engine again (Y page 83). When doing so,
remember 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. The engine will not
start. You can hear the
starter motor operat-
ing. 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 206). Troubleshooting
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Problem
Possible causes/consequences and
X XSolutions The engine will not
start. You cannot 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 234).
If the engine does not start despite attempting to jump-start it:
X Consult a qualified specialist workshop. The starter motor was exposed to a thermal load that was too high.
X
Allow the starter motor to cool down for approximately two
minutes.
X Try to start the engine again.
If the engine still does not start:
X Consult a qualified specialist workshop. Vehicles with a petrol
engine:
The engine is not run-
ning smoothly and is
misfiring. There is a malfunction in the engine electronics or a mechanical
component of the engine control unit.
X
Only depress the accelerator pedal slightly.
X Have the cause rectified immediately at a qualified specialist
workshop.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it. The coolant tempera-
ture gauge shows a
value above 120 †.
The coolant warning
lamp may also light up
and a warning tone may
sound (Y
page 90). The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
X
Stop as soon as possible and allow the engine and the coolant
to cool down.
X Check the coolant level (Y page 149). 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 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving on
mountain roads and stop/start driving. 208 TroubleshootingPractical advice
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Automatic transmission
Problem
Possible causes/consequences and
X
X Solutions The transmission has
problems shifting gear The transmission is losing oil.
X
Have the transmission checked at a qualified specialist work-
shop immediately. The acceleration ability
is deteriorating.
The transmission no
longer changes gear. The transmission is in emergency mode.
It is only possible to shift into
secondgear and reverse gear.
X Stop the vehicle.
X Turn the key to position 0(Y page 61) in the ignition lock.
X Wait at least 10 seconds before restarting the engine.
X Have the transmission checked at a qualified specialist work-
shop immediately. Parktronic*
Problem
Possible causes/consequences and
X
X Solutions Only the red segments
in the Parktronic warn-
ing display are lit. You
also hear a warning
tone for approximately
two seconds.
Parktronic is deactiva-
ted after approximately
20 seconds and the
indicator lamp in the
Parktronic 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 warn-
ing display are lit. Park-
tronic is deactivated
after approximately 20
seconds. The Parktronic sensors are dirty or there is interference.
X
Clean the Parktronic sensors (Y page 171).
X Switch the ignition back on. Troubleshooting
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Problem
Possible causes/consequences and
X XSolutions Only the red segments
in the Parktronic warn-
ing display are lit. Park-
tronic is deactivated
after approximately 20
seconds. The problem may be caused by an external source of radio or
ultrasound waves.
X
See if Parktronic functions in a different location. Headlamps
Problem
Possible causes/consequences and
X XSolutions The headlamps are mis-
ted 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 causes/consequences and
X XSolutions The windscreen wipers
are jammed. 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 completely.
G
Risk of accident
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
workshop. The windscreen washer
fluid from the spray
nozzles no longer hits
the centre of the wind-
screen. The spray nozzles are misaligned.
X
Have the spray nozzles adjusted at a qualified specialist work-
shop. 210 TroubleshootingPractical advice
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Side windows
Problem
Possible causes/consequences and
X
X Solutions A side window will not
close. Objects are trapped between the window and the door frame.
X
Remove the objects.
X Close the side window. There are objects in the window guide rail which are preventing
the window from closing.
X Remove the objects.
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 81). Mirrors
Problem
Possible causes/consequences and
X
X Solutions An exterior mirror has
been pushed out of
position.
Vehicles with exterior mirrors that cannot be folded in/out elec-
trically:
X
Move the exterior mirror into the correct position manually.
Vehicles with electrically folding exterior mirrors*:
X Press the mirror-folding button* (Y page 67) repeatedly until
you hear a distinct click.
The mirror housing is engaged again and you can adjust the
mirror as usual (Y page 67). Troubleshooting
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Key
Problem
Possible causes/consequences and
X XSolutions 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 unlock or lock the vehicle again.
If this does not work:
X Lock or unlock the vehicle using the emergency key element
(Y page 213).
X Check the key batteries (Y page 216) and replace them if nec-
essary ( Ypage 216). The key is faulty.
X
Lock or unlock the vehicle using the emergency key element
(Y page 213).
X Have the key checked at a qualified specialist workshop. The battery charge indi-
cator lamp of the key
does not go on during
the test. The key batteries are discharged.
X
Change the batteries ( Ypage 216). 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 emer-
gency key element.
X
Report the loss immediately to the vehicle insurers.
X If necessary, have the manual locks changed too. The engine cannot be
started using the key. The on-board voltage is too low.
X
Switch off non-essential consumers, e.g. seat heating* or inte-
rior lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary
(Y page 232).
or
X Jump-start the vehicle (Y page 234).
or
X Consult a qualified specialist workshop. 212 TroubleshootingPractical advice
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Problem
Possible causes/consequences and
X
X Solutions The engine cannot be
started using the key. The steering lock is mechanically blocked.
X
Remove the key and reinsert it into the ignition lock. While doing
this, turn the steering wheel in both directions. Parking up the vehicle
Problem
Possible causes/consequences and
X
X Solutions The vehicle is to be left
parked up for longer
than six weeks. Damage resulting from non-use may occur if the vehicle is parked
up for long periods.
X
Visit a qualified specialist workshop and seek advice.
X Disconnect the battery (Y page 233).Locking/unlocking in an emergency
Emergency key
If the vehicle can no longer be locked or
unlocked with the key, use the emergency
key element.
If you use the emergency key element to
unlock and open the driver's door, the anti-
theft alarm system* will be triggered
(Y page 54).
There are several ways to turn off the alarm:
X Press the %or& button on the key.
or
X Insert the key into the ignition lock.
If you unlock the vehicle using the emergency
key element, the fuel filler flap will not be
unlocked automatically. Releasing and removing the emergency
key element X
Push release catch :in the direction of
the arrow and at the same time remove
emergency key element ;from the key. Unlocking the vehicle
If the vehicle can no longer be unlocked cen-
trally with the key:
X Remove the emergency key element from
the key (Y page 213). Locking/unlocking in an emergency
213Practical advice
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