Page 292 of 373
Troubleshooting
289Problem Possible cause/consequence Suggested solutions
The fuel tank of a vehicle with a
diesel engine has been run com-
pletely dry and will not start. 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(Y page 76) 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
290 Engine
Problem Possible cause/consequence Suggested solutions
The engine will not start. You can
hear the starter motor operating. R
There is a malfunction in the
engine electronics.
R There is a malfunction in the
fuel supply. X
Turn the key back to position 0(Y page 76)in the ignition lock
before the next starting attempt.
X Try to start the engine again (Y page 110). 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. 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 289).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 329).
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. Practical advice
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Troubleshooting
291Problem Possible cause/consequence Suggested solutions
Vehicles with a petrol engine:
The engine is not running
smoothly and is misfiring. There is a malfunction in the
engine electronics or a mechani-
cal component of the engine con-
trol unit. 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. You also
hear a warning signal. 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 223). 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. driving on
mountain roads and stop/start driving. The engine does not switch off. The ignition lock is faulty. X
Open the fuse box in the engine compartment ( Ypage 334).
X Remove fuse 120 using the fuse extractor.
The engine stops.
If you wish to start the engine again:
X Replace the fuse. Practical advice
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Troubleshooting
292 Automatic 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(Y page 76) in the ignition lock.
X Wait at least 10 seconds before restarting the engine.
X Move the selector lever to position Dor R.
If D is selected, the transmission shifts into 2ndgear; if Ris 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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Page 300 of 373
Troubleshooting
297Problem Possible cause/consequence Suggested solutions
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 interior
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 323).
or
X Jump-start the vehicle (Y page 329).
or
X Consult a qualified specialist workshop. Practical advice
* optional
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Troubleshooting
299Problem Possible cause/consequence Suggested solutions
The vehicle cannot be started
using the KEYLESS GO key and
the KEYLESS GO button. The KEY-
LESS GO key is in the vehicle. A door is open. The key can there-
fore not be detected as easily. X
Close the door and try to start the vehicle again. You did not depress the brake
when starting the engine. X
Depress the brake and press the KEYLESS GO button. There is interference from a pow-
erful source of radio waves. X
Start your vehicle using the KEYLESS GO key in the ignition lock. You have lost the KEYLESS GO
key. X
Have the KEYLESS GO 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. Trailer towing*
Problem Possible cause/consequence Suggested solutions
The ball coupling cannot be
locked.
The key cannot be removed from
the ball coupling. G
Risk of accident
The ball coupling is dirty.
The trailer coupling is damaged. X
Remove the ball coupling and clean it (Y page 248). If the ball cou-
pling still cannot be locked, remove the ball coupling. It must no
longer be used to tow a trailer, as safe operation is not guaranteed.
X Have the entire trailer coupling checked at a qualified specialist
workshop. Practical advice
* optional
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Flat tyre
313Flat tyre
Flat tyre equipment variants
Your vehicle may be equipped with:
R a TIREFIT kit (Y page 252)
R an emergency spare wheel* ( Ypage 252)
R the MOExtended run-flat sys-
tem* (Y page 322) Preparing the vehicle
i Vehicle preparation is not necessary on
vehicles with MOE tyres*.
X Vehicles with the AIRMATIC package*:
Make sure that highway level* is selected
(Y page 154).
X Stop your vehicle as far away from traffic
as possible on solid, non-slippery, level
ground.
X Switch on the hazard warning lamps.
X Firmly depress the parking brake.
X Move the selector lever to P.X
All occupants must get out of the vehicle.
Make sure that they are not endangered as
they do so.
X Make sure that no one is near the danger
area whilst a wheel is being changed. Any-
one who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.
X Switch off the engine.
Vehicles without KEYLESS GO* X
Remove the key from the ignition lock.
Vehicles with KEYLESS GO* X
Open the driver's door.
The on-board electronics have status 0,
which is the same as the key having been
removed.
X Vehicles with the AIRMATIC package* and
the Off-Road Pro engineering package*:
Remove the KEYLESS GO button from the
ignition lock. For all vehicles X
Get out of the vehicle.
X Close the driver's door.
X Place the warning triangle ( Ypage 250) at
a suitable distance. Observe legal require-
ments.
i To operate the electric air-pump, you can
use the power socket in the luggage com-
partment (Y page 207) or 2nd row of seats
(Y page 207), even when the ignition is
switched off. For example, to use TIREFIT
or to inflate the collapsible emergency
spare wheel*.
An emergency cut-off ensures that the on-
board voltage does not drop too low. If the
on-board voltage is too low, power to the
sockets is automatically cut-off. This
ensures that there is sufficient power to
start the engine. Practical advice
* optional
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Flat tyre
318
Raising the vehicle G
Risk of injury
The jack is designed only to raise the vehi-
cle for a short time while a wheel is being
changed.
If you intend to work under the vehicle, it
must be placed on stands.
Make sure that the jack is placed on a firm,
non-slip, level surface. Do not use wooden
blocks or similar items as jacking supports.
Otherwise, the jack will not be able to ach-
ieve its load-bearing capacity due to the
restricted height.
Do not start the engine at any time while
the wheel is being changed.
Do not lie under the vehicle when it is being
supported by the jack. If you do not raise
the vehicle as described, it could slip off the
jack (e.g. if the engine is started or a door
or the tailgate is opened or closed) and you
could be seriously injured. G
Risk of accident
If you fail to position the jack correctly, the
vehicle may: R
slip off the jack
R injure you or others
R be damaged
It is thus important to ensure that the jack
is positioned correctly in the respective
jacking points. Before positioning the jack,
remove any dirt that may have collected in
the jacking points. 1
Wheel wrench
X Using wheel wrench 1, loosen the bolts on
the wheel you wish to change by about one
full turn. Do not unscrew the bolts com-
pletely.
The jacking points for the jack are located
behind the wheel housings of the front wheels and in front of the wheel housings of the rear
wheels (arrows). 1
Jacking point
2 Jack
3 Ratchet ring spanner
X Position jack 2at jacking point 1. Practical advice
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