2008 MERCEDES-BENZ CL550 key battery

687 Practical hints
Replacing SmartKey batteries
3Batteries
4Contact springs
Pull out batteries3.

Using a line-free cloth, insert new bat-
teries 3 under contact springs 4 with
the positive terminal (+) side facing up.

Return battery compartment 2 into
housing until it locks into place.

Slide the mechanical key back into the
SmartKey/SmartKey with
KEYLESS-GO*.

Check the operation of the SmartKey/
SmartKey with KEYLESS-GO*.

704 Practical hintsBatteries
Starter battery (example illustration from
CL 550)1Negative terminal
2Positive terminal
Disconnecting starter battery
Secure vehicle in place with electronic
parking brake (
page 412).

Shift the automatic transmission to
park positionP (
page 417).
Do not rub the battery with rags or cloths.
The battery could explode if touched due to
electrostatic charge or due to spark forma-
tion.!
Switch off the engine and switch off the ve-
hicle’s internal electrical functions (
page 705)
before you disconnect or remove the battery’s
terminal clamps. You could otherwise destroy
electronic assemblies such as the generator.
Have the battery checked regularly by an autho-
rized Mercedes-Benz Center. Refer to Mainte-
nance Booklet for maintenance intervals or
contact an authorized Mercedes-Benz Center for
further information.
!
Do not connect any consumers directly to
the starter battery. The starter battery will other-
wise be discharged.
i
Only replace a discharged battery with a bat-
tery recommended by Mercedes-Benz. The con-
sumer battery is installed in the trunk in such a
way that it is safeguarded as much as possible
against mechanical destruction in the event of
an accident.
i
Remove SmartKey from starter switch (vehi-
cles with KEYLESS-GO*: Make sure the vehicle’s
on-board electronics have status 0)
(
page 365) when you turn off the engine and
no longer require any electrical consumers. The
vehicle then uses very little power and the con-
sumer battery is spared.
i
If the consumer battery is discharged, you
must use the mechanical key to unlock the vehi-
cle (page 684). Since the vehicle has a sepa-
rate starter battery, however, you can still start
the vehicle.
!
Always disconnect the starter battery in the
order described below. You could otherwise
damage the vehicle’s electronics.
!
Switch off the vehicle’s internal electrical
functions before disconnecting the starter bat-
tery. If the vehicle is stationary for more than one
hour with the SmartKey removed, you do not
need to switch off the vehicle’s internal electrical
functions.


705 Practical hints
Batteries
Switching off vehicle’s internal
electrical functions
Turn off all electrical consumers.

Turn SmartKey in starter switch to po-
sition 0.

Turn SmartKey in starter switch to po-
sition 1.

Wait for 30 seconds.
The vehicle’s internal electrical func-
tions are switched off.

Turn SmartKey in starter switch to po-
sition 0.Disconnecting starter battery

Open the hood (
page 553).

Use a 10-mm open-end wrench to dis-
connect the battery negative lead.

Remove cover2 (
page 704) from
the positive terminal.

Disconnect the battery positive lead.
Removing starter battery
Pull out the battery ventilation hose
from the battery (depending on battery
arrangement in your vehicle model, the
ventilation hose is located either on the
left or right side of the battery).

Fold bar on starter battery up.

Take out the starter battery.
Charging battery
i
Vehicles with KEYLESS-GO: remove the
KEYLESS-GO button (
page 366) and use the
SmartKey with KEYLESS-GO like a normal
SmartKey.
!
Do not remove the SmartKey!
i
For your convenience, have the starter bat-
tery removed by a Mercedes-Benz Center.
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.i
Have the batteries charged by a
Mercedes-Benz Center. If you charge the batter-
ies yourself, follow the operating instructions for
your charging device.

706 Practical hintsBatteriesStarter battery
Connect the switched-off charging de-
vice to the terminals of the starter bat-
tery. Observe the operating
instructions in the manual for the
charging device while doing so.
Reinstalling starter battery
Install starter battery in engine com-
partment.

Swing retaining bar down.
Reconnecting starter battery

Make sure that the consumer battery in
the trunk is correctly installed and con-
nected.

Turn SmartKey in starter switch to po-
sition 0 and remove.

Connect the positive lead and fasten its
cover2 (
page 704).

Connect negative lead1
(page 704).

Attach ventilation tube.

Switch on the ignition (
page 365).

Start the engine (
page 406).

Check vehicle functions.
!
Only use charging devices with a maximum
charging voltage of 14.8 V.
Warning!
G
During the charge procedure, there is a risk
of acid burns due to gases escaping from
the battery. Do not bend over the battery
during the charge procedure.
!
The battery and the battery ventilation hose
must always be securely installed when the vehi-
cle is in operation.
!
Always connect the starter battery in the or-
der described below. Otherwise, the vehicle’s
electronics could be damaged.
Warning!
G
Do not drive without a properly installed and
connected consumer battery.
Have any work on the consumer battery car-
ried out by an authorized Mercedes-Benz
Center.
!
Never invert the terminal connections.
!
Make sure that the battery has a plug where
the ventilation tube is attached to it.

708 Practical hintsJump startingJump starting should only be performed on
the starter battery. The starter battery is
located in the engine compartment on the
passenger side (
page 704).

Make sure the two vehicles do not
touch.

Secure vehicle in place with electronic
parking brake (
page 412).

Shift the automatic transmission to
park positionP (
page 417).

Turn off all electrical consumers, ex-
cept hazard warning flashers or work
lights.

Open the hood (
page 553).

Start the engine of the vehicle with the
charged battery and run at idle speed.1Negative clamp
2Negative terminal of charged battery
3Positive terminal of charged battery
4Positive terminal of discharged battery
Warning!
G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(page 702).
i
Vehicles with KEYLESS-GO: remove the
KEYLESS-GO button (
page 366) and use the
SmartKey with KEYLESS-GO like a normal
SmartKey.

709 Practical hints
Jump starting

Remove red cover from positive
terminal4.

Connect positive terminal3 of the
charged battery with positive
terminal4 of the discharged battery
with the jumper cable. Clamp cable to
charged battery3 first.

Connect negative terminal2 of
charged battery to jumper cables and
attach other end of the jumper cable
with the negative clamp1 to a suit-
able ground point on the vehicle.

Get into vehicle and start engine within
30 seconds.
If the starting attempt does not suc-
ceed: 
Turn the SmartKey in starter switch
to position 0.

Take out the SmartKey.

Turn off engine of donor vehicle, re-
start it and let it run at idle speed
for several minutes.

Disconnect the jumper cable during
this time.

Reconnect jumper cable as de-
scribed before.

Restart engine.

While the engine is running, switch off
several electrical consumers such as
the blower.

Disconnect jumper cables first nega-
tive clamp1 from ground point and
negative terminal2, then from posi-
tive terminals4 and3.

Have the battery checked at the near-
est authorized Mercedes-Benz Center.
!
Never invert the terminal connections.

710 Practical hintsTowing the vehicleMercedes-Benz recommends that the
vehicle be transported with all wheels off
the ground using flatbed or appropriate
wheel lift/dolly equipment. This method is
preferable to other types of towing.
When circumstances do not permit the
recommended towing methods, the
vehicle may be towed with all wheels on
the ground or front axle raised only so far
as necessary to have the vehicle moved to
a safe location where the recommended
towing methods can be employed.!
To prevent damage during transport, do not
tie down vehicle by its chassis or suspension
parts.
!
Before towing the vehicle observe the fol-
lowing instructions:


Do not tow-start the vehicle.


Use flatbed or wheel lift/dolly equipment
with the ignition switched off.


Do not tow with sling-type equipment. Tow-
ing with sling-type equipment over bumpy
roads will damage radiator and supports.


Towing of the vehicle should only be done
using the properly installed towing eye bolt.
Never attach a tow cable, tow rope or tow
rod to the vehicle chassis, frame or suspen-
sion parts. For more information see “Install-
ing towing eye bolt” (
page 713).
i
If the battery is disconnected or discharged


the SmartKey will not turn in the starter
switch


the automatic transmission will remain
locked in park positionP.
For more information see “Batteries”
(
page 702) or “Jump starting” (
page 707).

744 IndexAudio AUX (COMAND) 125
Audio DVD
Fast forward/rewind (COMAND) 123
Menu overview (COMAND) 119
Pause function (COMAND) 121
Stop function (COMAND) 121
Auto-dimming, Rear view mirrors 383
Automatic climate control 491
Adjusting air distribution
(COMAND) 271
Adjusting air flow from air vents
(COMAND) 275
Adjusting air volume (COMAND) 271
Adjusting the footwell temperature
(COMAND) 274
Air recirculation mode 496
Central climate control menu
(COMAND) 272
Defrosting 494
Operating via COMAND 269
Rear window defroster 496
Selecting Mono mode
(COMAND) 273
Setting temperature (COMAND) 270
Setting the temperature 494Switching cooling on or off
(COMAND) 272
Automatic headlamp mode 301, 392
Automatic lighting control, Interior
lighting 398
Automatic locking when driving 363
Automatic shift program 427
Automatic transmission
Accelerator position 424
Automatic shift program 427
Emergency operation
(Limp-Home Mode) 433
Fluid 733
Fluid level 558
Gear ranges 426
Gear selector lever 417
Gear shifting malfunctions 433
Hill start assist system 425
Kickdown 424
Kickdown, manual shift program
(CL 63 AMG and CL 65 AMG) 432
Manual shift program mode
(CL 63 AMG and CL 65 AMG) 430
Program mode selector switch 427
Shifting procedure 420Starting the engine 406
Steering wheel gearshift control 428
Transmission fluid 558
Transmission positions 421
AUX
Audio 125
Video 126
AUX jacks 125
B
Backup lamps
Replacing bulbs 689
Bar 586
BAS 67
Batteries, SmartKey
Checking battery condition 361
Replacing 686
Batteries, SmartKey with KEYLESS-GO*
Checking battery condition 361
Replacing 686
Batteries, vehicle 702
Charging 705
Discharged, Jump starting 707
Disconnecting 704
For electrical consumers 702
For starter 702