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
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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
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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
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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
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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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Locking/unlocking in an emergency
302 Locking/unlocking in an emergency
Emergency key
If the vehicle can no longer be unlocked or
locked with the key or the KEYLESS GO
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 63).
There are several ways to turn off the alarm:
X Press the korj button on the key.
or
X Insert the key into the ignition lock.
or
X Press the KEYLESS GO button* in the igni-
tion lock. The KEYLESS GO key* must be in
the vehicle.
or
X Lock or unlock the vehicle using KEYLESS
GO*. The KEYLESS GO key* must be out-
side the vehicle. Releasing and removing the emergency
key element
1
Release catch
2 Emergency key element
X Push release catch 1in the direction of
the arrow and at the same time remove
emergency key element 2from the key. Unlocking the vehicle
If the vehicle can no longer be unlocked cen-
trally with the key or the KEYLESS GO key*:
X Remove the emergency key element from
the key (Y page 302). $
To unlock
X Insert the emergency key element into the
lock of the driver's door as far as it will go.
X Firmly turn the emergency key element
anti-clockwise as far as it will go to position
$ and hold it in this position.
i On right-hand-drive vehicles, turn the
emergency key element clockwise.
X Pull the door handle firmly.
The locking knob pops up.
The door is unlocked. Practical advice
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Locking/unlocking in an emergency
303
X
Turn the emergency key element back and
remove it.
X Pull the door handle again. Locking the vehicle
If the vehicle can no longer be locked cen-
trally with the key or the KEYLESS GO key*:
X Close the front-passenger door, the rear
door on the front-passenger side and the
tailgate.
X Open the driver's door and the rear door on
the driver's side.
X Press the locking button on the driver's
door (Y page 75).
The locking knobs in the front-passenger
door and in the rear doors drop down.
X Press the locking knobs in the front-
passenger and rear doors down manually if
necessary.
X Exit the vehicle.
X Close the driver's door.
X Enter the vehicle through the rear door on
the driver's side.
X Push the locking pin in the driver's door
down from the inside.
X Exit the vehicle. i
Ensure that you have the vehicle key on
your person and that it is not left in the
vehicle, as the vehicle will be locked after
the next step.
X Close the rear door on the driver's side.
The vehicle is locked. Emergency fuel filler flap release
G
Risk of injury
The edges on the inside of the vehicle body
can be sharp. You could injure yourself
when using the fuel filler flap emergency
release. Avoid contact with the edges on
the inside of the vehicle body.
The emergency release is located behind the
right-hand side trim panel in the luggage com-
partment.
X Open the tailgate.
X Open the right-hand side trim panel
(Y page 310). 1
Emergency release
X Pull emergency release 1in the direction
of the arrow.
The fuel filler flap is unlocked.
X Open the fuel filler flap. Practical advice
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Changing the batteries
304 Resetting triggered NECK-PRO head
restraints
If the NECK-PRO head restraints are triggered
in an accident, you must reset the head
restraints on the driver's and front-passenger
seats. Otherwise, the additional protection
will not be available in the event of another
rear-end collision. You can recognise when
head restraints have been triggered by the
fact that they have been moved forwards and
can no longer be adjusted.
Mercedes-Benz recommends that you have
NECK-PRO head restraints checked at a quali-
fied specialist workshop, e.g. a Mercedes-
Benz Service Centre, following a rear-end
collision.
i This work requires a lot of strength. If you
have difficulty resetting the head
restraints, have this work carried out at a
qualified specialist workshop, e.g. a
Mercedes-Benz Service Centre. 1
To move forwards
2 To push down
3 To push back
X Move the top of the head restraint cushion
forwards in the direction of arrow 1.
X Push the head restraint cushion down in
the direction of arrow 2as far as it will go.
X Push the head restraint cushion firmly
backwards in the direction of arrow 3until
it engages.
X Repeat this procedure for the second head
restraint. Changing the batteries
Notes
It is advisable to have the batteries replaced
at a qualified specialist workshop, e.g. at a
Mercedes-Benz Service Centre. G
Risk of poisoning
Batteries contain toxic and caustic sub-
stances. For this reason, keep batteries
away from children.
If a battery is swallowed, consult a doctor
immediately. H
Environmental note
Do not dispose of batteries with the house-
hold rubbish. They contain highly toxic sub-
stances.
Take discharged batteries to a qualified
specialist workshop, e.g. a Mercedes-Benz
Service Centre, or to a special collection
point for old batteries. Practical advice
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