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Troubleshooting
294 Headlamps 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
251_AKB; 5; 7, en-GB
wobuchh
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Troubleshooting
295Windows
Problem Possible cause/consequence Suggested solutions
A side window will not close. Something is 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 being raised. 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 ( Ypage 107). 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* ( Ypage 90) repeatedly until you
hear a distinct click.
The mirror housing is engaged again and you can adjust the mirror
as usual (Y page 90). Practical advice
* optional
251_AKB; 5; 7, en-GB
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Troubleshooting
296 Key
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 unlock or lock the vehicle again.
If this does not work:
X Unlock the vehicle using the emergency key element
(Y page 302).
X Check the key batteries (Y page 305) and replace them if neces-
sary (Y page 305). The key is faulty. X
Unlock the vehicle using the emergency key element
(Y page 302).
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 305).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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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
251_AKB; 5; 7, en-GB
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Troubleshooting
298 KEYLESS GO*
Problem Possible cause/consequence Suggested solutions
You cannot lock or unlock the
vehicle using the KEYLESS GO
key. The KEYLESS GO key batteries
are discharged or nearly dis-
charged. X
Lock or unlock the vehicle using the remote control function of the
key. To do this, 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 Unlock the vehicle using the emergency key element
(Y page 302).
X Check the KEYLESS GO key batteries (Y page 305) and replace
them if necessary (Y page 305). There is a fault with KEYLESS GO. X
Lock or unlock the vehicle using the remote control function of the
key. To do this, point the tip of the key at the driver's door handle
from close range and try to open the vehicle again.
X Have the KEYLESS GO key checked at a qualified specialist work-
shop. There is interference from a pow-
erful source of radio waves. X
Unlock the vehicle using the emergency key element
(Y page 302). The battery check lamp in the
KEYLESS GO key does not light
up when tested. The KEYLESS GO key batteries
are discharged. X
Change the batteries (Y page 305).Practical advice
* optional
251_AKB; 5; 7, en-GB
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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
251_AKB; 5; 7, en-GB
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Troubleshooting
300 Auxiliary heating/ventilation*
Problem Possible cause/consequence Suggested solutions
The auxiliary heating is not work-
ing. The fuel level is down to the
reserve level. X
Refuel at the nearest filling station. The battery is not sufficiently
charged. X
Charge the battery. The auxiliary heating is faulty. X
Have the auxiliary heating checked at a qualified specialist work-
shop. The auxiliary heating cannot be
switched on or off using the
remote control. The remote control display shows
FAIL and the
¢symbol.
The signal transmission between
the remote control and the vehi-
cle is faulty. X
Change your position in relation to the vehicle, moving closer if
necessary.
X Make another attempt to switch the auxiliary heating on or off using
the remote control. The remote control display shows
FAIL and the
¡symbol.
There is not enough fuel in the
tank, or the auxiliary heating is
faulty. X
Refuel at the nearest filling station.
X Have the auxiliary heating checked at a qualified specialist work-
shop. Practical advice
* optional
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Page 304 of 373
Troubleshooting
301Parking up the vehicle
Problem Possible cause/consequence Suggested 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 ( Ypage 325). Practical advice
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