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Display messages
Possible causes/consequences and
X
X Solutions  Close
doors to
lock vehi‐
cle At least one door is open.
X
Close all doors and lock the vehicle again. & inopera‐
tive Bat‐
tery low The on-board voltage is too low. The auxiliary heating/venti-
lation* has switched off or cannot be switched on.
X
Drive for a longer distance.
The battery is being charged. The auxiliary heating/venti-
lation *can be reactivated as soon as there is sufficient on-
board voltage. & inopera‐
tive
Refuel
vehicle The fuel level in the fuel tank is too low. The auxiliary heat-
ing* cannot be switched on.
X
Refuel at the nearest filling station. & inopera‐
tive See
Owner's
Manual
The auxiliary heating
*is temporarily malfunctioning or is
defective.
X When the vehicle is on a level surface and the engine has
cooled down, make up to four attempts to switch on the
auxiliary heating*, waiting several minutes between each
attempt.
X If the auxiliary heating* does not switch on, visit a qualified
specialist workshop. + Top up
coolant
See Own‐
er's Man‐
ual The coolant level is too low.
X
Top up the coolant, observing the warning notes before
doing so (Y page 294).
X Have the engine cooling system checked at a qualified spe-
cialist workshop if the coolant needs topping up more often
than usual. ? Coolant
Stop vehi‐
cle Turn
engine off The coolant is too hot.
X
Pull over and stop the vehicle safely and switch off the
engine, paying attention to road and traffic conditions.
X Make sure that the air supply to the radiator is not blocked,
e.g. by slush.
X Wait until the display message disappears before restarting
the engine. Otherwise, there is a risk of engine damage.
X Observe the coolant temperature gauge. 342
Display messagesPractical advice
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Display messages
Possible causes/consequences and
X
X Solutions The poly-V-belt may have torn.
X
Stop immediately and safely when traffic conditions permit
and check the poly-V-belt.
If the poly-V-belt is torn:
X Do not drive on. Consult a qualified specialist workshop.
If the poly-V-belt is intact:
X Wait until the display message disappears before restarting
the engine. Otherwise, there is a risk of engine damage.
X Observe the coolant temperature gauge.
X Have the vehicle checked at a qualified specialist work-
shop. b Third
brake lamp The third brake lamp is faulty. The display message will only
appear if all LEDs have failed.
X
Visit a qualified specialist workshop. b Left-hand
cornering
light
or
Right-
hand cor‐
nering
light The left-hand or right-hand cornering lamp is faulty.
X
Change the bulb (Y page 369). b Left-hand
dipped
beam
or
Right-
hand
dipped
beam The left-hand or right-hand dipped-beam headlamp is faulty.
X
Visit a qualified specialist workshop. b Active
Light
Function
inopera‐
tive
The active light function* is faulty.
X
Visit a qualified specialist workshop. Display
messages
343Practical advice
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Display messages
Possible causes/consequences and
X
X Solutions b AUTO
lights
inopera‐
tive The light sensor is faulty. Daytime driving lights are switched
on.
X
Switch off the daytime driving lights in the on-board com-
puter (Y page 225).
X Switch the lighting on or off using the light switch.
X Visit a qualified specialist workshop. b Rear left-
hand turn
signal
or
Rear
right-
hand turn
signal The rear left-hand or right-hand turn signal is faulty.
X
Visit a qualified specialist workshop. b Turn sig‐
nal in
left-hand
exterior
mirror
or
Turn sig‐
nal in
right-
hand exte‐
rior mir‐
ror The left-hand or right-hand turn signal on the exterior mirror
is faulty. The display message will only appear if all LEDs have
failed.
X
Visit a qualified specialist workshop. b Front
left-hand
turn sig‐
nal
or
Front
right-
hand turn
signal The front left-hand or right-hand turn signal is faulty.
X
Visit a qualified specialist workshop. b Left-hand
main beam
or
Right-
hand main
beam The left-hand or right-hand main beam headlamp is faulty.
X
Change the bulb (Y page 369).344
Display
messagesPractical advice
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Display messages
Possible causes/consequences and
X
X Solutions b Left-hand
licence
plate lamp
or
Right-
hand
licence
plate lamp The left-hand or right-hand licence plate lamp is faulty.
X
Visit a qualified specialist workshop. b Switch
off lights The lights are still switched on when you leave the vehicle.
X
Turn the light switch to $orc.
or
X If the rear foglamp is switched on: press the light switch in
to the stop. b Left-hand
foglamp
or
Right-
hand fog‐
lamp The front left-hand or right-hand foglamp is faulty.
X
Visit a qualified specialist workshop. b Rear left-
hand fog‐
lamp
or
Rear
right-
hand fog‐
lamp The rear left-hand or right-hand foglamp is faulty.
X
Visit a qualified specialist workshop. b Front
left-hand
parking
lamp
or
Front
right-
hand park‐
ing lamp The left-hand or right-hand side lamp is faulty.
X
Visit a qualified specialist workshop. Display
messages
345Practical advice
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Display messages
Possible causes/consequences and
X
X Solutions b Left-hand
reversing
lamp
or
Right-
hand
reversing
lamp The left-hand or right-hand reversing lamp is faulty.
X
Visit a qualified specialist workshop. b Left-hand
tail lamp/
brake lamp
or
Right-
hand tail
lamp/
brake lamp The left-hand or right-hand tail lamp/brake lamp is faulty. The
display message will only appear if all LEDs have failed.
X
Visit a qualified specialist workshop. b Intell.
Light Sys‐
tem inop‐
erative The Intelligent Light System is faulty. The lights remain avail-
able without the Intelligent Light System.
X
Visit a qualified specialist workshop. Á Night
View
Assist
inopera‐
tive
Night View Assist* is faulty.
X
Visit a qualified specialist workshop. Á Night
View
Assist
currently
unavaila‐
ble The temperature of the camera is too high.
X
Wait until you see the Night View Assist available
again display message.
You can also:
X Fold the camera cover down (Y page 311).
X Adjust the air distribution of the automatic air conditioning
upwards. Á Night
View
Assist
Lights
must be
on or set
to AUTO
A condition for activating Night View Assist* has not been
met.
X
Turn the light switch to corL. 346
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Display messages
Possible causes/consequences and
X
X Solutions Á Night
View
Assist
Not in
Reverse
A condition for activating Night View Assist* has not been
met.
X
Shift the transmission to P,Nor D. Á Night
View
Assist
Lights on
or AUTO,
not in
Reverse
A condition for activating Night View Assist* has not been
met.
X
Turn the light switch to corL.
X Shift the transmission to P,Nor D. Á Night
View
Assist
only when
it is dark
You have attempted to activate Night View Assist* in the day-
time.
Night View Assist* can only be activated when it is dark.
4 Engine
oil level
Stop vehi‐
cle Turn
engine off There is insufficient oil in the engine. There is a risk of engine
damage.
X
Pull over and stop the vehicle safely and switch off the
engine, paying attention to road and traffic conditions.
X Top up and check the engine oil level (Y page 293).4 Top up
with 1
litre of
engine
oil when
next refu‐
elling
The engine oil level is too low
38
.
X Check the engine oil level ( Ypage 293).
X If necessary, top up the engine oil.
X Have the engine checked for leaks if the engine oil needs
topping up more often than usual. 4 Engine
oil level
Reduce
oil level
You have added too much engine oil
38
. The engine or catalytic
converter may be damaged.
X Siphon off excess engine oil until it is at the specified level.
Observe the legal requirements. 4 Engine
oil level
cannot be
measured
The measuring system is malfunctioning
38
.
X Visit a qualified specialist workshop. 38
Only on certain vehicles. Display
messages
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Display messages
Possible causes/consequences and
X
X Solutions 4 Check
engine
oil level
when next
refuelling The engine oil level has dropped to a critical level.
X
Check the engine oil level ( Ypage 293).
X If necessary, top up the engine oil.
X Have the engine checked for leaks if the engine oil needs
topping up more often than usual. h Tyre pres‐
sure Cau‐
tion,
tyre
defect
G
Risk of accident
Vehicles with the tyre pressure monitor*: the pressure is
dropping rapidly in one or more of the tyres.
X Stop the vehicle without making any sudden steering or
braking manoeuvres. Pay attention to traffic conditions as
you do so.
X Repair the faulty tyre or replace the wheel (Y page 373).h Tyre pres‐
sure
Check
tyre(s)
G
Risk of accident
Vehicles with tyre pressure monitor*: the tyre pressure has
dropped significantly in one or more of the tyres.
X Stop the vehicle without making any sudden steering or
braking manoeuvres. Pay attention to traffic conditions as
you do so.
X Repair the faulty tyre or replace the wheel (Y page 373)._ Front
left seat
backrest
not locked
or
Front
right
seat back‐
rest not
locked
G
Risk of injury
The driver's or front passenger's seat backrest is not
engaged. The seat belt will have no effect.
X Engage the driver's seat or front passenger's seat backrest. C There is only a small amount of fuel in the fuel tank.
X
Refuel at the nearest filling station. 8 Reserve
fuel level The fuel level has fallen below the reserve range. The opera-
tion of the auxiliary heating
* can nolonger be guaranteed.
X Refuel at the nearest filling station. ¥ Top up
washer
fluid The washer fluid level has sunk to about 1 litre.
X
Top up the windscreen washer fluid (Y page 295).348
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Troubleshooting
Points to remember
G
Risk of accident and injury
The operating safety of your vehicle may be affected if service work is carried out incorrectly.
You could lose control of your vehicle and cause an accident. In addition, the safety systems may
no longer be able to protect you or others as they are designed to do.
Always have service work performed at a qualified specialist workshop which has the necessary
specialist knowledge and tools to carry out the work required. Mercedes-Benz recommends that
you use a Mercedes-Benz Service Centre for this purpose. In particular, work relevant to safety
or on safety-related systems must be carried out at a qualified specialist workshop. Warning and indicator lamps in switches, buttons and exterior mirrors
Problem
Possible causes/consequences and
X
X Solutions The seat ventilation*
has switched itself off
prematurely. The on-board voltage is too low, because too many consumers are
switched on.
X Switch off consumers that are not required, e. g. the reading
lamp or interior lighting. The seat heating has
switched itself off pre-
maturely. The on-board voltage is too low, because too many consumers are
switched on.
X Switch off consumers that are not required, e. g. the reading
lamp or interior lighting. The cooling system
cannot be switched on
using COMAND. Cooling has been deactivated due to a malfunction.
X
Visit a qualified specialist workshop. The rear-window heat-
ing has switched off
prematurely or cannot
be switched on. The on-board voltage is too low, because too many consumers are
switched on.
X Switch off consumers that are not required, e. g. the reading
lamp or interior lighting.
Once the battery is sufficiently charged, the rear window heating
will switch back on automatically. Troubleshooting
349Practical advice
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