2008 MERCEDES-BENZ C300 key battery

448 Practical hints
Battery
Starter battery
1Battery
2Positive terminal
3Negative terminal
4Ventilation hose
Disconnecting the battery
Apply the parking brake (page 134).
Make sure gear selector lever* is set to
positionP (manual transmission to
Neutral).
Turn off all electrical consumers.
Remove SmartKey from starter switch.Vehicles with KEYLESS-GO* (Canada
only):
Press the start / stop button until
the engine shuts off.
Open the driver’s door.
Open the hood (page 325).
Remove the filter box (page 447).
Read and observe safety instructions
and precautions (
page 446).
Disconnect the battery negative lead
from negative terminal3.
Remove cover from the positive
terminal2.
Disconnect the battery positive lead.iIf the battery is discharged, you must use
the mechanical key to unlock (
page 424) or
lock (
page 425) the vehicle.
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 (Canada only) will have no effect

vehicles with automatic transmission*:
the gear selector lever will remain
locked in positionP
!Always disconnect the starter battery in the
order described below. You could otherwise
damage the vehicle’s electronics.

450 Practical hints
Battery
Reconnecting the battery
Turn off all electrical consumers.
Remove SmartKey from starter switch.
Vehicles with KEYLESS-GO* (Canada
only):
Open the driver’s door.
Connect the battery positive lead and
fasten its cover (
page 448).
Connect the battery negative lead
(
page 448).
Make sure that the ventilation hose4
is attached to the battery.
Reinstall filter box (page 447).
!Always connect the starter battery in the or-
der described below. Otherwise, the vehicle’s
electronics could be damaged.
!Never invert the terminal connections.
!Make sure the battery has a plug where the
ventilation hose
4 is attached to it.
iThe following procedures must be carried
out following any interruption of battery power
(e.g. due to reconnecting):

Reset the automatic exterior mirror fold in
function (
page 99).

Set the clock (page 170).
Vehicles with COMAND*: see COMAND op-
erator’s manual.

454 Practical hints
Towing the vehicle
Warning!G
Without the engine running, there is no pow-
er assistance for the brake and steering sys-
tems. In this case, it is important to keep in
mind that a considerably higher degree of
effort is necessary to brake and steer the
vehicle. Adapt your driving accordingly.
iWhen towing the vehicle with all wheels on
the ground, please note the following:
With the automatic central locking activated and
the SmartKey or SmartKey with KEYLESS-GO*
(Canada only) in starter switch position 2, the ve-
hicle doors lock if the left front wheel as well as
the right rear wheel are turning at vehicle speeds
of approximately 9 mph (15 km/h) or more.
To prevent the vehicle doors from locking,
deactivate the automatic central locking
(
page 173).
!If the vehicle is towed with the front axle
raised (not permissible for vehicles with
4MATIC), the gear selector lever must be in
positionN (manual transmission: gear shift lever
in neutral position) and the engine must be shut
off (SmartKey or SmartKey with KEYLESS-GO*
(Canada only) in starter switch position0 or1).
Active braking action through the ESP
® may
otherwise seriously damage the brake system.
While towing, the battery must be connected and
charged. Otherwise:

you will not be able to switch on the ignition

you will not be able to engage the automatic
transmission* in positionN (
page 127)
When towing the vehicle with all wheels on the
ground, the gear selector lever must be in
positionN (manual transmission: gear shift lever
in neutral position) and the SmartKey or
SmartKey with KEYLESS-GO* (Canada only)
must be in starter switch position2.
!Towing of the vehicle should only be done
using the properly installed towing eye bolt.
Never attach tow cable, tow rope or tow rod to
vehicle chassis, frame or suspension parts.
iTo signal turns while being towed with the
hazard warning flasher in use, turn SmartKey or
SmartKey with KEYLESS-GO* (Canada only) in
starter switch to position2 and activate the
combination switch for the left or right turn sig-
nal in the usual manner – only the selected turn
signal will operate.
Upon canceling the turn signal, the hazard
warning flasher will operate again.
!Make sure the parking brake is released.
iIf the battery is disconnected or discharged

the SmartKey or SmartKey with KEY-
LESS-GO* (Canada only) will not turn in the
starter switch

Vehicles with automatic transmission*: the
gear selector lever will remain locked in
positionP (
page 127).
For more information see “Battery”
(
page 446) and see “Jump starting”
(
page 451).

488 Index
Phone cook 233
Radio operation 194
Satellite radio* operation 200
Sound settings 189
Surround sound* (Canada only) 190
SYS menu 192
SYS menu, Bluetooth
® settings 192
SYS menu, display settings 192
SYS menu, language settings 193
SYS menu, reset to factory
settings 193
Telephone menu* 222
Volume 189
Auto-dimming*, Rear view mirrors 100
Automatic central locking 80
Activating/deactivating
(Control system) 173
Automatic climate control (3-zone) see Cli-
mate control system
Automatic headlamp mode 109, 172
Automatic lighting control, Interior
lighting 115
Automatic shift program 144Automatic transmission
Accelerator position 142
Emergency operation (limp-home
mode) 146
Fluid 476, 477
Fluid level 328
Gear ranges 143
Gear shifting malfunctions 146
Hill start assist system 246
Kickdown 142
Shifting procedure 139
Starting the engine 127
Transmission fluid 328
Automatic transmission*
Automatic shift program 144
Gear selector lever 138
Gear selector lever control one-touch
gearshifting 145
Gear selector lever positions 140
Program mode selector switch 144
Aux socket 220B
Backrest 281
Backup lamps
Replacing bulbs 430, 431
Bar 356
BAS 60
Batteries, SmartKey
Checking battery condition 78
Replacing 428
Batteries, SmartKey with KEYLESS-GO*
(Canada only)
Checking battery condition 78
Replacing 428
Battery 448
Battery, vehicle 446
Charging 449
Discharged, Jump starting 451
Disconnecting 448
Message in display 399
Reconnecting 450
Removing 449
Bead 356
Beverage holder see Cup holder

496 Index
Interior rear view mirror
Adjusting 97
Auto-dimming 99, 100
Interior storage spaces see
Storage compartments
J
Jack 421
Jump starting 451K
Key, Mechanical 424
Loss of 79
Key, SmartKey 70
Battery check lamp 70, 72
Factory setting 71
Global locking and unlocking 71
Lock button 70
Locking and unlocking 70
Loss of 79
Messages in display 408
Opening button for trunk 70
Panic button 58
Remote control 70
Restoring to factory setting 73
Selective setting 72
Starting the engine 127
Steering wheel lock 82
Switching on ignition with 82
Turning off engine 135
Unlock button 70Key, SmartKey with KEYLESS-GO* 73
Battery check lamp 73, 77
Closing, Trunk 269
Factory setting 76
Global locking and unlocking 77
Important notes on using
KEYLESS-GO* 75
Locking and unlocking 73
Opening button for trunk 73
Panic button 58
Restoring to factory setting 78
Selective setting 77
Starting the engine 128
Switching on ignition with 84
Unlock button 73
Key, SmartKey with KEYLESS-GO*
(Canada only)
Lock button 73
Loss of 79
Messages in display 407
Remote control 73
Turning off engine 135
Kickdown 142
Kilopascal 357

497 Index
L
Labels 462
Certification 462
Emission control information 463
Tire and Loading Information 335
Lamps, exterior 431
Light sensor 409
Lamps, indicator and warning
ABS 27, 59, 374
Air bag Off 40
Battery check lamp (SmartKey with
KEYLESS-GO* 77
Battery check lamp (SmartKey) 72
Brake warning lamp 27
Brakes 376
Engine diagnostics 27, 378
Engine malfunction 27, 378
ESP
®27, 376, 379, 380
Front passenger front air bag off 29,
45, 385, 386
Fuel reserve 380
High beam headlamps 27
Instrument cluster 374–383
Maintenance service indicator 362
Seat belt telltale 27, 380
SRS 27, 382Turn signals 27
Language 193
Language, Setting 168
LATCH-type child seat anchors see
Children in the vehicle
Lever
For cruise control 242
License plate lamps
Messages in display 411
Replacing bulbs 431, 437
Light alloy wheels, Cleaning 370
Light sensor
Message in display 409
Lighter see Cigarette lighter
Lighting 108
Automatic headlamp mode 109
Corner-illuminating front fog
lamps* 112
Daytime running lamp mode 110
Door entry lamps 116
High beam flasher 112
Instrument cluster illumination 148
Interior 114
Manual headlamp mode 108
Trunk 116
Limp-home mode 146Loading see Vehicle loading
Locator lighting 172
Lock button
Door handle (KEYLESS-GO*, Canada
only) 76, 125
Key, SmartKey 70
Key, SmartKey with KEYLESS-GO*
(Canada only) 73
Locking 133
Vehicle in an emergency 425
Locking knob 79
Loss of
Key, Mechanical 79
Key, SmartKey 79
Key, SmartKey with KEYLESS-GO*
(Canada only) 79
Service and Warranty Information
Booklet 461
Low beam headlamps
Replacing bulbs (Bi-Xenon*) 431
Replacing bulbs (Halogen) 431, 433
Lowering
Vehicle 445
Lubricants 476
Lumbar support* 91

498 Index
M
Maintenance 11, 362
Automatic Call (Tele Aid*) 302
Calling up service indicator
display 363
Clearing service indicator
message 362
Maintenance System 362
Resetting service indicator 363
Service indicator message 362
Service term exceeded 363
Vehicles with E85 fuel 483
Manual headlamp mode 108
Manual transmission 136, 137
Gearshift lever 126, 137
Shift positions 137
Starting the engine 127
Maximum load rating, Tires 357
Maximum loaded
vehicle weight 340, 357
Maximum tire
inflation pressure 354, 357
Maximum tire load rating 353
Memory function* (Canada only) 102
Menus see Control systemMessages in display see
Multifunction display messages
Microphone, Hands-free 31
Minispare wheel 422, 471
Mounting 441
Mirrors
Activating exterior rear view mirror
parking position*
(Canada only) 101
Adjusting 97
Auto-dimming* for rear view
mirrors 100
Exterior rear view mirrors 97
Interior rear view mirror 97
Modifications and alterations,
Operating safety 15
MON 478
MP3
Playback options 220
Selecting a folder 219
Selecting a track 219
Multifunction display 151
Changing settings see Control system
menus and Control system sub-
menusMultifunction display messages
ABS 389, 398
Battery, vehicle 399
Brake fluid 400
Brake pads 399
Coolant 402
Coolant level 405
Doors 406
EBP (Electronic Brake
Proportioning) 401
ESP
®389, 397, 398
Fog lamps 410
Front passenger front air bag 393
Fuel cap 406
Gear selector lever 392
Headlamps 411
Hood 406
Key, SmartKey 408
Key, SmartKey with KEYLESS-GO*
(Canada only) 407
Lamps, exterior 409
License plate lamps 411
Light sensor 409
Low tire pressure 418
Parking brake 401
Parking lamps 411