2005 MERCEDES-BENZ SLK CLASS battery

379 Practical hints
Replacing SmartKey batteries
SmartKey
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key
(page 374).
1Mechanical key
2Battery compartment

Insert mechanical key1 in side open-
ing and push gray slide.
Battery compartment2 is unlatched.

Pull battery compartment2 out of the
housing in direction of arrow.

Remove the discharged batteries.
3Battery
4Contact spring

Using a lint-free cloth, insert new
batteries3 under contact spring4
with the plus (+) side facing up.

Return battery compartment2 into
the housing until it engages.

Slide mechanical key1 back into the
SmartKey.

Check the operation of the SmartKey.

396 Practical hintsBatteryThe battery is located in the engine com-
partment on the right-hand side below the
windshield washer fluid reservoir.
1Battery
2Positive terminal
3Negative terminal
Warning!
G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and precau-
tions when handling automotive batteries,
see “Battery” (
page 294).
Never lean over batteries while connecting
them, as you could otherwise be injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come into contact with
eyes, skin or clothing. In case it does, imme-
diately 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.
Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof batteries only to avoid the
risk of acid burns in the event of an acci-
dent.!Never loosen or detach battery termi-
nal clamps while the engine is running
or the SmartKey is in the starter switch.
Otherwise the alternator and other
electronic components could be se-
verely damaged.
Have the battery checked regularly by
an authorized Mercedes-Benz Center.
Refer to Maintenance Booklet for main-
tenance intervals or contact an autho-
rized Mercedes-Benz Center for further
information.

397 Practical hints
Battery
Disconnecting the battery
1Water tray
2Lock

Depress parking brake firmly or move
g e a r s e l ec t o r le v e r * t o p o s it io nP (man-
ual transmission to Neutral).

Switch off all electrical consumers.

Remove SmartKey from starter switch.

Open the hood (
page 287).

Turn locks2 one quarter turn.

Remove water tray1.

Read and observe safety instructions
and precautions (
page 396).

Disconnect the battery negative lead.

Remove the cover from the positive
terminal.

Disconnect the battery positive lead.
Removing the battery
Remove the screw on the swivel bar.

Remove the swivel bar.

Take out the battery.
Charging and reinstalling battery
Warning!
G
With a disconnected battery

you will no longer be able to turn the
SmartKey in the starter switch


automatic transmission*: the gear se-
lector lever will remain locked in
positionP
Warning!
G
Never charge a battery while still installed in
the vehicle unless the accessory battery
charge unit approved by Mercedes-Benz is
being used. Gases may escape during charg-
ing and cause explosions that may result in
paint damage, corrosion or personal injury.
An accessory battery charge unit specially
adapted for Mercedes-Benz vehicles and
tested and approved by Mercedes-Benz is
available, permitting the charging of the bat-
tery in its installed position. Contact an
authorized Mercedes-Benz Center for infor-
mation and availability. Charge battery in
accordance with the separate instructions
for the accessory battery charger.


398 Practical hintsBattery
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.
Reconnecting the battery
Switch off all electrical consumers.

Connect the positive lead and fasten its
cover.

Connect the negative lead.

Reinstall the water tray.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 133).


Resynchronize side windows
(page 236).


399 Practical hints
Jump 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 (12V). Jump start-
ing 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 the jumper cables
are not on or near pulleys, fans, or oth-
er 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, as you could otherwise be
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.
Attempting to jump start a frozen battery
can result in it exploding, causing personal
injury.
Read all instructions before proceeding.
!Avoid repeated and lengthy starting at-
tempts.
Do not attempt to start the engine us-
ing a battery quick charge unit.
If the 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.

400 Practical hintsJump starting
Make sure the two vehicles do not
touch.

Switch off all electrical consumers.

Apply parking brake.

Shift gear selector lever* to positionP
(manual transmission to Neutral).

Open the hood (
page 287).

Remove the cover from positive under
hood terminal2 in front of discharged
battery.1Positive terminal of charged battery
2Positive under hood terminal in front of
discharged battery
3Negative under hood terminal in front
of discharged battery
4Negative terminal of charged battery

Connect positive terminal1 of the
charged battery with positive under
hood terminal2 in front of the dis-
charged battery with one jumper cable.
Clamp the cable to positive terminal1
of the charged battery first.

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

Connect negative terminal4 of the
charged battery with negative under
hood terminal3 in front of the dis-
charged battery with the second jump-
er cable. Clamp the cable to negative
terminal4 of the charged battery
first.

Start the engine of the disabled vehi-
cle.
You can now switch on the electrical con-
sumers. Do not switch on the lights under
any circumstances.

Remove the jumper cables first from
negative terminals3 and4 and then
from positive terminals2 and1.
You can now switch on the lights.

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 294).
!Never invert the terminal connections.
iVehicles with automatic transmission*:
Do not tow-start vehicle.

403 Practical hints
Towing the vehicle
Installing towing eye bolt
The towing eye bolt is supplied with the ve-
hicle tool kit, located in the compartment
underneath the trunk floor (
page 369).
The towing eyes are located on the passen-
ger side in the front and rear bumper.

Take vehicle tool kit out of trunk
(page 369).1Cover in front bumper
2Cover in rear bumper

Press mark on corresponding cover1
or2 in direction of arrow for folding
down.

Lift cover off to reveal threaded hole for
towing eye bolt.
Do not remove cover completely.

Screw towing eye bolt in to its end stop
and tighten with lug wrench.

For removing towing eye bolt and rein-
stalling cover, follow the previously de-
scribed steps in reverse order.
iThe gear selector lever* will remain
locked in positionP (vehicles with au-
tomatic transmission*) and the Smart-
Key will not turn in the starter switch if
the battery is disconnected or dis-
charged. See notes on the battery
(page 396) or on jump starting
(page 399).
Vehicles with automatic transmission*:
For information on manual unlocking of
transmission selector lever, see
(page 376).
iWhen closing the cover, insert the
latches first and gently press on the
opposite side until the cover fully en-
gages.
Make sure the cover’s check strap
does not get caught when closing.

419 Technical data
Electrical system
Electrical system
Model
SLK 350
SLK 55 AMG
Generator (alternator)
14 V/150 A
14 V/150 A
Starter motor
12 V/1.7 kW
12 V/1.7 kW
Battery
12 V/74 Ah
12 V/74 Ah
Spark plugs
Bosch Platin Y 7 MPP33
NGK PLKR 6A
NGK IFR6D10
Electrode gap
0.031 in (0.8 mm)
0.039 in (1.0 mm)
Tightening torque
15 – 22 lb-ft (20 – 30 Nm)
18 – 22 lb-ft (25 – 30 Nm)