Page 358 of 506

356 Practical hintsWhat to do if …Lamps in instrument clusterGeneral information:
If any of the following lamps in the instru-
ment cluster fails to come on during thebulb self-check when switching on the igni-
tion, have the respective bulb checked and
replaced if necessary.Problem
Possible cause
Suggested solution
-
The yellow ABS malfunction indi-
cator lamp comes on while driv-
ing.
The ABS has detected a malfunction and has
switched off. The BAS and the ESP are also
switched off (see messages in display).
The SBC brake system is still functioning nor-
mally but without the ABS available.
If the ABS control unit is malfunctioning, oth-
er systems such as the Parktronic system*,
Distronic*, or the automatic transmission
may also be malfunctioning.
Continue driving with added caution.
Wheels may lock during hard braking,
reducing steering capability.
Read and observe messages in the
display (
page 367).
Have the system checked at an autho-
rized Mercedes-Benz Center as soon
as possible.
Failure to follow these instructions in-
creases the risk of an accident.
The charging voltage has fallen below
10 volts. The ABS has switched off.
The battery may not be sufficiently charged.
Switch off electrical consumers that
are currently not needed, e.g. seat
heating.
If necessary, have the generator and
battery checked.
When the voltage is above this value
again, the ABS is operational again.
Page 372 of 506
370 Practical hintsWhat to do if …Display
Display message
Possible cause
Possible solution
Low
Battery
Conven. functions
temporarily
unavailable
The battery has insufficient voltage
and can no longer supply conve-
nience functions such as the rear
window defroster.
As soon as the on-board voltage is sufficient,
the consumers will switch on again.
Please note:
Conven. functions
available again
On-board voltage is sufficient; the
consumers will switch on again.
Cruise control
Drive to workshop
Cruise control or Distronic* is mal-
functioning.
Have the cruise control or Distronic*
checked by an authorized Mercedes-Benz
Center.
Distronic
External interference
Reactivate
The Distronic* is switched off and is
temporarily unavailable.
Try activating the Distronic* again later.
Drive to workshop
The Distronic* is malfunctioning or
the display is malfunctioning.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Page 380 of 506
378 Practical hintsWhat to do if …Symbol messagesDisplay symbol
Display messages
Possible cause
Possible solution
#
Undervoltage
Switch off
consumers
The battery has insufficient voltage.
Turn off unnecessary electrical con-
sumers.
Visit workshop
The battery is no longer charging.
Possible causes:
alternator malfunctioning
broken poly-V-belt
Do not forget that the brake system re-
quires electrical energy and may be oper-
ating with restricted capability.
Considerably greater brake pedal force is
required and the stopping distance is in-
creased.
Stop immediately and check the
poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise
the engine will overheat due to an in-
operative water pump which may re-
sult in damage to the engine. Notify
an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest au-
thorized Mercedes-Benz Center. Ad-
just driving to be consistent with
reduced braking responsiveness.
Page 381 of 506

379 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
#
Battery/Alternator
Stop vehicle
The battery is malfunctioning.
The SBC brake system requires electrical
energy and therefore has only limited op-
eration. Considerably greater brake pedal
force is required and the stopping dis-
tance is increased.
Stop the vehicle as soon as it is safe
to do so. Adjust driving to be consis-
tent with reduced braking responsive-
ness.
Notify an authorized Mercedes-Benz
Center.
Low voltage
Start engine
The battery has insufficient voltage.
Start the engine (
page 46).
Malfunction
Electrical consumers
switched off
The consumer battery has insufficient
voltage and can no longer supply the con-
venience functions such as seat ventila-
tion*.
The electrical consumers will come back
online as soon as on-board voltage is suf-
ficient.
(
Backrest, right rear
not locked
The rear seat backrest is not engaged.
Adjust the rear seat backrest until it is
fully engaged in position.
Backrest, left rear
not locked
The rear seat backrest is not engaged.
Adjust the rear seat backrest until it is
fully engaged in position.
Page 382 of 506

380 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
2
Brake wear
Visit workshop
The brake pads have reached their wear
limit.
Brake pad thickness must be visually
inspected at the intervals specified in
the Maintenance Booklet.
Have the brake pads replaced as soon
as possible.
T
Reduced braking power
Depress brake
pedal fully
The SBC brake system is in emergency
operation mode. Considerably greater
brake pedal force is required and the
stopping distance is increased.
The maximum speed is limited to 55 mph
(90 km / h).
Do not drive any further.
Stop the vehicle and notify an autho-
rized Mercedes-Benz Center.
Prevent the vehicle from rolling away
by blocking the wheels with wheel
chocks or other sizable objects.
Call for Roadside Assistance.
(USA only);(Canada only)3
Reduced braking power
Start engine
The battery has insufficient voltage and
cannot supply sufficient power to the
SBC brake system.
Start the engine.
The message disappears when suffi-
cient voltage is available.
Page 393 of 506
391 Practical hints
What to do if …
Display symbol
Display messages
Possible cause
Possible solution
F
Key
Check battery
The SmartKey with KEYLESS-GO* batter-
ies are discharged.
Change the batteries (
page 415).
Key
not recognized
The SmartKey with KEYLESS-GO* is not
recognized while the engine is running
because
the SmartKey with KEYLESS-GO* is
not in the vehicle
there is strong radio-frequency inter-
ference
Stop the vehicle as soon as it is safe
to do so.
Search for the SmartKey.
Otherwise the vehicle cannot be cen-
trally locked nor can the engine be
started again after the engine is
stopped.
The SmartKey with KEYLESS-GO* is mo-
mentarily not recognized.
Change the position of the SmartKey
in the vehicle.
Operate the vehicle with the
SmartKey in the starter switch if nec-
essary.
Page 406 of 506

404 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
L
Tele Aid malfunction
Drive to workshop
One or more main functions of the
Tele Aid system are malfunctioning.
Have the Tele Aid system checked by
an authorized Mercedes-Benz Center.
Tele Aid battery
Drive to workshop
The emergency power battery for the
Tele Aid system is malfunctioning. If the
vehicle battery is also dead, Tele Aid will
not be operational.
Have the Tele Aid system checked by
an authorized Mercedes-Benz Center.
1
Restraint system
malfunction
Drive to workshop
The system is malfunctioning.
Drive with added caution to the near-
est authorized Mercedes-Benz Cen-
ter.
Warning!
G
In the event a malfunction of the SRS is indi-
cated as outlined above, the SRS may not be
operational.
For your safety, we strongly recommend
that you visit an authorized Mercedes-Benz
Center immediately to have the system
checked; otherwise the SRS may not be
activated when needed in an accident,
which could result in serious or fatal injury,
or it might deploy unexpectedly and unnec-
essarily which could also result in injury.
Page 417 of 506

415 Practical hints
Replacing SmartKey batteries
Replacing SmartKey batteries
If the batteries in the SmartKey are dis-
charged, the vehicle can no longer be
locked or unlocked. It is recommended to
have the batteries replaced at an autho-
rized 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.
SmartKey
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key1
(page 410).
1Mechanical key
2Battery compartment
Insert the mechanical key1 in side
opening and push gray slide.
Battery compartment2 is unlatched.
Pull battery compartment2 out of the
housing in direction of arrow.
Remove the batteries.
Warning!
G
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 re-
place both batteries.
The required replacement batteries are
available at any Mercedes-Benz Cen-
ter.