2006 MERCEDES-BENZ SL55AMG Batteries

389 Practical hints
Replacing SmartKey batteries
Replacing SmartKey batteries
If the batteries in the SmartKey or the
SmartKey with KEYLESS-GO* 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 mechanical key1
(page 385).
1Mechanical key
2Slide
3Battery compartment

Insert mechanical key1in direction
of arrow into side opening.

Using mechanical key1, push gray
slide2to unlatch battery compart-
ment 3.

Pull battery compartment3out of the
housing in direction of arrow.

Remove the batteries in direction of ar-
row.
4Battery
5Contact spring

Using a lint-free cloth, insert new bat-
teries 4 under contact spring 5 with
the positive terminal (+) facing up.

Return battery compartment 3 into
housing until it locks into place.

Slide mechanical key 1 back into the
SmartKey.

Check the operation of the SmartKey.
Warning!
G
Keep the batteries out of reach of children.
If a battery is swallowed, seek medical help
immediately.iWhen inserting batteries, make sure
they are clean and free of lint.

390 Practical hintsReplacing SmartKey batteriesSmartKey with KEYLESS-GO*
Replacement battery: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key
(page 385).

Take the battery compartment out of
the SmartKey housing (
page 389).1Battery
2Tilt battery up
3Mechanical key

Using mechanical key3, apply pres-
sure to position 2.
Battery 1 tilts up slightly.

Pull out battery 1 in direction of ar-
row.

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

Return the battery compartment into
the housing until it locks into place.

Slide mechanical key 1 back into the
SmartKey, see “SmartKey”
(page 389).

Check the operation of the SmartKey
with KEYLESS-GO.
iWhen replacing batteries, always re-
place both batteries. The required re-
placement batteries are available at
any authorized Mercedes-Benz Center.

413 Practical hints
Batteries
Batteries
For more information on batteries, see
“Battery” (
page 279).
Your vehicle is equipped with two
batteries:


The starter battery


The battery for electrical consumers
(consumer battery), located in the
trunkThe starter battery is located on the
right-hand side of the engine compart-
ment.
1Positive terminal
2Negative terminalThe consumer battery is located on the
right-hand side of the trunk.
3Positive terminal
4Negative terminal
!The starter battery, its filler caps, and
the vent tube must always be securely
installed when the vehicle is in opera-
tion.
!The consumer battery located in the
trunk is a valve-regulated lead acid
(VRLA) battery, also referred to as
“fleece” battery. Such batteries do not
require topping-up of the electrolyte
level. VRLA batteries therefore do not

414 Practical hintsBatteries
have cell caps and the battery cover is
non-removable. Do not attempt to
open the consumer battery as other-
wise the battery will be damaged.
Even though VRLA batteries do not
require topping-up of the electrolyte
level and cannot be opened to check
the electrolyte level, the battery condi-
tion must be checked periodically by
performing a battery conductance test.
Refer to Maintenance Booklet for bat-
tery condition testing intervals.
As with any other battery, disconnect
the consumer battery if you do not in-
tend to operate your vehicle for an
extended period of time to prevent bat-
tery discharge or connect an accessory
battery charge unit expressly approved
by Mercedes-Benz for your vehicle
model to maintain the battery charge.
Contact an authorized Mercedes-Benz
Center for further information.
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 SmartKey is in the starter switch.
Otherwise the alternator and other
electronic components could be se-
verely damaged.
Have the starter battery checked regu-
larly 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.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.

415 Practical hints
Batteries
Disconnecting the batteries
Make sure the gear selector lever is set
to position P.

Close the retractable hardtop
(page 195).

Turn off the engine (
page 60).

Turn off all electrical consumers.

Remove the SmartKey from the starter
switch.
or

Vehicles with KEYLESS-GO*: Open the
driver’s door.
Warning!
G
The brake system requires electrical power
to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. The same applies if
battery is disconnected. To brake, the driver
must then apply significantly greater brake
pedal pressure and depress the pedal much
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the
brake pedal. Brakes are only applied to the
front wheels. Stopping distance is in-
creased! Adjust your driving style according-
ly. For more information, see
“Electro-hydraulic brake system”
(page 88).
Warning!
G
With a disconnected battery

you will no longer be able to turn the
SmartKey in the starter switch and
pressing the KEYLESS-GO* start/stop
button on the gear selector lever will
have no effect


the gear selector lever will remain
locked in positionP
!Always disconnect the batteries in the
order described below, even if you only
want to charge the starter battery, for
example. Otherwise the vehicle’s
electronics can be damaged.


416 Practical hintsBatteries
Depress the parking brake pedal.

Open the trunk.

Read and observe safety instructions
and precautions (
page 279).

Unhook the luggage cover in the trunk.

Remove the trunk floor.
The battery for electrical consumers is
located in the right hand area of the
trunk (
page 383).

Use the 10 mm open-end wrench from
the vehicle tool kit to disconnect the
negative lead from negative
terminal4 of the consumer battery
(page 413).

Open the hood (
page 272).

Use the 10 mm open-end wrench from
the vehicle tool kit to disconnect the
negative lead from negative
terminal2 of the starter battery
(page 413).

Remove the covers from the positive
terminals 1 and 3 (
page 413).

Disconnect the positive lead from pos-
itive terminal 3 of the consumer bat-
tery (
page 413).

Disconnect the positive lead from pos-
itive terminal 1 of the starter battery
(page 413).
Removing the batteries
Removing the consumer battery
Remove the screws securing the bat-
tery in the trunk.

Remove the battery support and
bracket.

Pull out the battery ventilation tube
from the battery.
Depending on battery arrangement in
your vehicle model, the ventilation tube
is located either on the left or right side
of the battery.

Take out the battery.


417 Practical hints
Batteries
Removing the starter battery
Remove the screws securing the start-
er battery in the engine compartment.

Pull out the battery ventilation tube
from the battery.
Depending on battery arrangement in
your vehicle model, the ventilation tube
is located either on the left or right side
of the battery.

Lift the retaining bracket.

Remove the battery.
Charging and reinstalling batteries
Charge batteries in accordance with
the instructions of the battery charger
manufacturer.

Reinstall the charged batteries. Follow
the previously described steps in re-
verse order.
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 au-
thorized Mercedes-Benz Center for
information and availability. Charge battery
in accordance with the separate instruc-
tions for the accessory battery charger.

418 Practical hintsBatteriesReconnecting the batteries
Turn off all electrical consumers.

Install starter battery in the designated
location in the engine compartment.

Install consumer battery in the desig-
nated location in the trunk.

Attach supports and brackets.

Tighten support and bracket screws.

Connect positive lead 3 of the con-
sumer battery and positive lead 1 of
the starter battery and fasten covers.

Connect negative lead 2 of the starter
battery.

Connect negative lead 4 of the con-
sumer battery.

Reinstall the trunk floor.

Rehook trunk luggage cover into hold-
ers.
!Always connect the batteries in the
order described below. Otherwise the
vehicle’s electronics can be damaged.!Never invert the terminal connections!
iThe following procedures must be car-
ried out following any interruption of
battery power (e.g. due to reconnec-
tion):

Resynchronize the ESP
®
(
page 354).


Resynchronize side windows
(page 194).