2003 MERCEDES-BENZ C240 4MATIC battery

278 Practical hintsWhat to do if …Display
Possible cause
Suggested solution
#
UNDERVOLTAGE
ENGINE ON!
The battery has insufficient voltage and
can no longer supply the convenience
functions such as seat heater*.

Start the engine (
page 44).
UNDERVOLTAGE
SWITCH CONSUMERS OFF!
The battery is malfunctioning.

Have the battery checked at a service
station.
G
VISIT WORKSHOP!
DISPLAY DEFECTIVE
The instrument cluster display is
malfunctioning.

Continue driving with added caution.

Visit an authorized Mercedes-Benz
Center as soon as possible.
±
VISIT WORKSHOP!
DISPLAY DEFECTIVE
Certain electronic systems are unable to
relay information to the control system.
The following systems may have failed:

Coolant temperature display


Tachometer


Cruise control display

Have the electronic systems checked
by an authorized Mercedes-Benz
Center (
page 259).
W
WASHER FLUID
CHECK LEVEL!
The fluid level has dropped to about
1/3
of total reservoir capacity.
Add washer fluid (
page 241).

286 Practical hintsUnlocking/locking in an emergencyLocking the vehicle
If you are unable to lock the vehicle with
the SmartKey, lock it with the mechanical
key as follows:
Close the passenger doors and the
trunk.

Press the central locking switch in the
cockpit (
page 92).

Check to see whether the locking
knobs on the passenger doors are still
visible. If necessary push them down
manually.

Lock the driver’s door with the me-
chanical key (
page 285).

Check if the trunk is locked. If neces-
sary lock the trunk with the mechanical
key (
page 90).
Changing 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.Warning!
G
Keep the batteries out of reach of children.
If a battery is swallowed, seek medical help
immediately.
iWhen changing batteries, always re-
place both batteries.
The required replacement batteries are
available at any Mercedes-Benz
Center.

287 Practical hints
Unlocking/locking in an emergency
SmartKey
1Mechanical key
2Battery compartment
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove mechanical key1
(page 285).

Insert the mechanical key in side open-
ing and push gray slide.
The battery compartment2 is un-
latched.

Pull the battery compartment2 out of
the key housing in direction of arrow.3Battery
4Contact spring

Remove the batteries.

Using a lint-free cloth, insert new bat-
teries under the contact spring with the
plus (+) side facing up.

Return battery compartment into hous-
ing until it locks into place.
Fuel filler flap
Open trunk lid.

Fold away right-side tail lamp trim.

Reach inside through opening2.

Turn release knob1 clockwise (arrow).
The fuel filler flap can now be opened.

303 Practical hints
Battery
Battery
The battery is located in the engine com-
partment on the right hand side.
Removal of filter box:
Release the three clamps1.

Remove filter box.
Installation of filter box:

Insert filter box properly.

Secure it with the three clamps1.
Warning!
G
Failure to follow these instructions can re-
sult in severe injury or death.
Never lean over batteries while connecting,
you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.
!Never loosen or detach battery termi-
nal clamps while the engine is running
or the key is in the starter switch. Oth-
erwise the alternator and other elec-
tronic components could be severely
damaged.
Have the battery checked regularly by
an authorized Mercedes-Benz Center.
Refer to Service Booklet for mainte-
nance intervals or contact your autho-
rized Mercedes-Benz Center for further
information.Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof battery only to avoid the risk
of acid burns in the event of an accident.

304 Practical hintsBattery1Negative terminal
2Positive terminal cover
Disconnecting the battery
Turn off all electrical consumers.

Open the hood (
page 235).

Remove the filter box.

Disconnect the battery negative
lead1.

Remove the cover2 from the positive
terminal.

Disconnect the battery positive lead.
Removing the battery
Remove the screw-nuts securing the
battery.

Remove the battery bracket.

Take out the battery.
Charging and reinstalling the battery
Charge battery in accordance with the
instructions of the battery charger
manufacturer.

Reinstall the charged battery. Follow
the previously described steps in re-
verse order.
Warning!
G
With a disconnected battery

y o u w i l l n o l o n g e r b e a b l e t o t u r n t h e k e y
in the starter switch will have no effect


the selector lever will remain locked in
positionP
Warning!
G
Never charge a battery while still installed in
the vehicle. Gases may escape during charg-
ing and cause explosions that may result in
paint damage, corrosion or personal injury.

305 Practical hints
Battery
Reconnecting the battery
Turn off all electrical consumers.

Connect the positive lead and fasten its
cover.

Connect the negative lead.

Reinstall the filter box (
page 303).Batteries contain materials that can harm
the environment if disposed of improperly.
Large 12 volt storage batteries contain
lead. Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
!NEVER invert the terminal connections!!The battery, its filler caps and the vent
tube must always be securely installed
when the vehicle is in operation.
iThe following procedures must be car-
ried out following any interruption of
battery power (e.g. due to reconnec-
tion):

Set the clock (
page 120)
Vehicles with COMAND*:
see COMAND operator’s manual.


Resynchronize the front seat head
restraints (
page 94).


Resynchronize the ESP
(page 75).


Resynchronize side windows
(page 189).


Resynchronize sliding/pop-up
roof* (
page 191).

306 Practical hintsJump starting
Jump starting
If the battery is discharged, the engine can
be started with jumper cables and the bat-
tery of another vehicle. Observe the follow-
ing:

Jump starting should only be performed
when the engine and catalytic convert-
er are cold.


Do not start the engine if the battery is
frozen. Let the battery thaw out first.


Only jump start from batteries with the
same voltage rating (12 V). Jump
starting with a more powerful battery
could damage the vehicle’s electrical
system, which will not be covered by
the Mercedes-Benz Limited Warranty.


Only use jumper cables with sufficient
cross-section and insulated terminal
clamps.


Always make sure that the jumper
cables are not on or near pulleys, fans,
or other parts that move when an
engine is started or running.
Warning!
G
Failure to follow these directions will cause
damage to the electronic components, and
can lead to a battery explosion and severe
injury or death.
Never lean over batteries while connecting
or jump starting, you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water, and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and very explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.
Read all instructions before proceeding.
!Jump starting may only be performed
on the battery installed in the engine
compartment.
Avoid repeated and lengthy starting at-
tempts.
Do not attempt to start the engine
using a battery quick charge unit.
If engine does not run after several
unsuccessful starting attempts, have it
checked at the nearest authorized
Mercedes-Benz Center.
Excessive unburned fuel generated by
repeated failed starting attempts may
damage the catalytic converter and
may present a fire risk.
Make sure the jumper cables do not
have loose or missing insulation.
Make sure the cable clamps do not
touch any other metal part while the
other end is still attached to a battery.

307 Practical hints
Jump starting
The battery is located in the engine
compartment on the right hand side. The
terminals for jump starting are located in
front of the battery.
Make sure that the two vehicles do not
touch.

Turn off all electrical consumers.

Apply parking brake.

Shift selector lever to positionP (man-
ual transmission to Neutral).1Positive terminal of charged battery
2Positive under hood terminal in front of
discharged battery
3Negative terminal of charged battery
4Negative under hood terminal in front
of discharged battery

Connect positive terminal1 of the
charged battery with the under hood
terminal2 in front of the discharged
battery with the jumper cables. Clamp
cable to charged battery1 first.

Start engine of the vehicle with the
charged battery and run at idle speed.

Connect negative terminal3 of the
charged battery with the under hood
terminal4 of the discharged battery
with the jumper cables. Clamp cable to
charged battery3 first.

Start the engine of the disabled vehi-
cle.
Now you can again turn on the electrical
consumers. Do not turn on the lights under
any circumstances.

Remove the jumper cables first from
negative terminals3 and4 and then
from positive terminals1 and2.

Have the battery checked at the near-
est authorized Mercedes-Benz Center.
Warning!
G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(page 240).
!Vehicles with automatic transmission
and/or 4MATIC*:
Do not tow-start the vehicle.