Page 328 of 425
327 Practical hints
What to do if ...
Symbol messages
Left displayRight displayPossible cause/
consequencePossible solution
malfunctionThe Airbrake locking mecha-
nism is malfunctioning.Contact an authorized Mercedes-Benz Center
immediately.
#Battery/Alternator
Stop carThe battery is malfunctioning.
The electro-hydraulic brake
system requires electrical
energy and therefore has only
limited operation. Considerably
greater brake pedal force is
required and the pedal travel is
longer. The stopping distance is
increased. If necessary, apply
full pressure to the brake pedal.Stop the vehicle as soon as it is safe to do so. Adjust
driving to be consistent with reduced braking
responsiveness.
Do not drive any further.
Call Roadside Assistance.
Contact an authorized Mercedes-Benz Center
immediately.
Page 330 of 425

329 Practical hints
What to do if ...
Left displayRight displayPossible cause/
consequencePossible solution
TReduced
brake effect
Depress brake
pedal fully!The electro-hydraulic brake
system is in emergency opera-
tion mode. Considerably great-
er brake pedal force is required
and the pedal travel is longer.
The stopping distance is in-
creased. If necessary, apply full
pressure to the brake pedal.
The maximum speed is limited
to 55 mph (90 km/h).Stop the vehicle in a safe location or as soon as it is safe
to do so.
Apply the parking brake (page 55).
Do not drive any further.
Prevent the vehicle from rolling away by blocking the
wheels with wheel chocks or other sizeable objects.
Contact an authorized Mercedes-Benz Center.
or
Call for Roadside Assistance.
Warning!G
Driving while this message is displayed can
result in an accident. Have your brake
system checked immediately.
If the electro-hydraulic brake system enters
its emergency operation mode, the driver
must apply significantly greater brake pedal
pressure and depress the pedal much fur-
ther than normal to obtain braking effect.
If necessary, apply full pressure to the brake
pedal. Brakes are only applied to the front
wheels. Stopping distance is increased!
If there is a malfunction in the
electro-hydraulic brake system, we recom-
mend that the vehicle be transported with
all wheels off the ground using flatbed or ap-
propriate wheel lift/dolly equipment.A tow bar must be used if circumstances do
not permit the use of the recommended
towing methods and the vehicle requires
towing with all four wheels on the ground.
Towing the vehicle with all four wheels on
the ground is only permissible for distances
up to 30 miles (50 km) and at a speed not to
exceed 30 mph (50 km/h). For more infor-
mation, see “Towing the vehicle”
(
page 370).
Page 332 of 425

331 Practical hints
What to do if ...
Left displayRight displayPossible cause/
consequencePossible solution
;(USA only)
3(Canada only)
Reduced
brake effect
Visit
workshopThe electro-hydraulic
brake system is in emer-
gency operation mode.
Considerably greater
brake pedal force is
required and the pedal
travel is longer. The stop-
ping distance is in-
creased. If necessary,
apply full pressure to the
brake pedal.Stop the vehicle in a safe location or as soon as it is
safe to do so.
Apply the parking brake (page 55).
Do not drive any further.
Prevent the vehicle from rolling away by blocking the
wheels with wheel chocks or other sizable objects.
Contact an authorized Mercedes-Benz Center.
or
Call for Roadside Assistance.
Increased
stopping distance
Visit
workshop
Warning!G
Driving while these messages are displayed
can result in an accident. Have your brake
system checked immediately.
If the electro-hydraulic brake system enters
its emergency operation mode, the driver
must apply significantly greater brake pedal
pressure and depress the pedal much fur-
ther than normal to obtain braking effect.
If necessary, apply full pressure to the brake
pedal. Brakes are only applied to the front
wheels. Stopping distance is increased!
If there is a malfunction in the
electro-hydraulic brake system, we recom-
mend that the vehicle be transported with
all wheels off the ground using flatbed or ap-
propriate wheel lift/dolly equipment.A tow bar must be used if circumstances do
not permit the use of the recommended
towing methods and the vehicle requires
towing with all four wheels on the ground.
Towing the vehicle with all four wheels on
the ground is only permissible for distances
up to 30 miles (50 km) and at a speed not to
exceed 30 mph (50 km/h). For more infor-
mation, see “Towing the vehicle”
(
page 370).
Page 335 of 425

334 Practical hints
What to do if ...
Left displayRight displayPossible cause/
consequencePossible solution
;(USA only)
3(Canada only)
Service brake
Visit
workshopThere are malfunctions, but the
electro-hydraulic brake system
is operating normally.Contact an authorized Mercedes-Benz Center
immediately.
Release
parking brakeYou are driving with the parking
brake set.Release the parking brake (page 49).
2 Brake wearThe brake pads have reached
their wear limit.Have the brake pads replaced as soon as pos-
sible.
!Brake pad thickness must be visually
checked by a qualified technician at the intervals
specified in the Maintenance Booklet.
Excessive load on the brake system causes in-
creased wear of brake pads and brake disks. If
the brake pads have to be replaced multiple
times within one maintenance service interval,
the brake disks must be checked. Observe the
information given in the Maintenance Booklet
and contact an authorized Mercedes-Benz
Center.Warning!G
Have brake pad replacement and other work
on the electro-hydraulic brake system car-
ried out by qualified technicians only. Con-
tact your Mercedes-Benz Center for further
information. The electro-hydraulic brake
system must be deactivated prior to working
on the system. High pressure is intermit-
tently built up in the system as part of its
automatic self-test. In addition, the system
is automatically activated when the vehicle
is unlocked by remote control, when the
driver or passenger door is opened, when
the SmartKey in the starter switch is turned
to position1, when the brake pedal is
depressed or when the parking brake is
released.
Failure to deactivate the system prior to
maintenance will cause brake pistons to
extend and brake fluid to leak, which may
result in injuries (contusions and acid
burns), see “Electro-hydraulic brake sys-
tem” (
page 86).
Page 356 of 425
355 Practical hints
Unlocking in an emergency
Unlocking in an emergency
Unlocking the vehicle
Unlocking the trunk
If you cannot unlock the trunk with the
SmartKey, open the trunk with the
mechanical key.
The handle is located above the rear
license plate recess.1Mechanical key locking tab
2Mechanical key
Press locking tab1 in the direction of
arrow and, at the same time, remove
mechanical key2 completely out of
the housing.
Trunk lid lock
3Unlocking
Insert the mechanical key in the trunk
lid lock.
Perform the following two steps
simultaneously:
Turn the mechanical key
counterclockwise to the stop, to
position3.
Pull the trunk lid handle and lift the
trunk lid.
iUnlocking the trunk with the mechanical key
will trigger the anti-theft alarm system when the
door is opened.
To cancel the alarm, insert the SmartKey in the
starter switch.
Page 357 of 425
356 Practical hints
Unlocking in an emergency
Unlocking the driver’s door
If you can no longer lock or unlock the
doors using the SmartKey, unlock the
driver’s door using the emergency release
catch.The emergency release catch is located on
the left side in the trunk.
1Emergency release catchUnlock the trunk (page 355).
Pull emergency release catch1.
The door is unlocked.
Open the door in the normal way.
Contact an authorized Mercedes-Benz
Center.
iUnlocking the driver’s door with the emer-
gency release catch will trigger the anti-theft
alarm system.
To cancel the alarm, insert the SmartKey in the
starter switch.
iIf it still is not possible to unlock the door,
pull more firmly on the emergency release catch.
Page 358 of 425

357 Practical hints
Replacing SmartKey batteries
Replacing SmartKey batteries
If the batteries in the SmartKey are
discharged, the vehicle can no longer be
locked or unlocked. It is recommended to
have the batteries replaced at an
authorized Mercedes-Benz Center.Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key out of the
SmartKey (
page 355).Warning!G
Batteries contain poisonous and corrosive
substances. Therefore keep the batteries
out of reach of children.
If a battery is swallowed, seek medical help
immediately.
iWhen inserting the batteries, make sure
they are clean and free of lint.
iWhen replacing batteries, always replace
both batteries. The required replacement batter-
ies are available at any Mercedes-Benz Center.
Page 359 of 425
358 Practical hints
Replacing SmartKey batteries
1Mechanical key
2Unlocking the battery compartment
3Removing the battery compartment
4Slide
Insert mechanical key1in side
opening, push gray slide4 in direction
of arrow2.
The battery compartment is unlatched.
Pull battery compartment out of the
housing in direction of arrow3.5Battery
6Contact spring
Remove the discharged batteries.
Using a lint-free cloth, insert new
batteries5 under the contact
spring6 with the plus (+) side facing
up.
Return battery compartment into
housing until it locks into place.
Slide mechanical key1 back into the
SmartKey.
Check the operation of the SmartKey.