2001 MERCEDES-BENZ E-Class key battery

364 Electronic main key
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index
Insert mechanical key (4) in side opening (5) to open
latch. Press briefly (do not use mechanical key as lever)
to release battery compartment.
Remove mechanical key from side opening.
Carefully remove battery compartment in direction of
arrow (6).Change batteries (7), inserting new ones under contact
spring (8) with plus (+) side facing up.
Return battery compartment into housing until locked
in place and slide mechanical key back into electronic
main key.
P80.35-2025-26
5
4
6
P80.35-2027-26
78

365 Electronic main key
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index Important!
Batteries contain materials that can harm the
environment if disposed of improperly. Recycling of
batteries is the preferred method of disposal. For
disposal, please follow manufacturer’s recommendation
on battery package.
Replacement Battery:
Lithium, type CR 2025 or equivalent.Synchronizing remote control
The remote control may have to be resynchronized, if
the vehicle cannot be locked or unlocked.
To synchronize insert electronic key in starter switch.
The remote control should once again be operational.

367 KEYLESS-GO-card
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index Changing batteries
Pry open cover (1) (e.g. by using a narrow blade screw
driver) and remove batteries.
Install new batteries as indicated by the “+” and “-”
markings in the KEYLESS-GO-card.Important!
Batteries contain materials that can harm the
environment if disposed of improperly. Recycling of
batteries is the preferred method of disposal. For
disposal, please follow manufacturer’s recommendation
on battery package.
Replacement batteries:
Lithium, type CR 2025 or equivalent.

403 Index
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car careIndex Front center console storage
compartment ventilation .................................... 175
Rear window defroster ............................................. 180
Residual engine heat utilization (REST) ............... 174
Special settings ......................................................... 169
Switching on and off ................................................ 175
Automatic climate control, rear
Air volume, manual .................................................. 178
Basic setting .............................................................. 178
Automatic transmission ...............................................233
Emergency operation ............................................... 241
Fluid level ...................................................................335
Program mode selector switch ...............................240
Selector lever position ..............................................236
BBabySmart
TM airbag deactivation system ..................... 91
Self-test ......................................................................... 91
BAS (Brake assist system) ............................................ 271
Battery .............................................................................349
Battery recycling .......................................................350
BATTERY / ALTERNATOR -
malfunction and warning messages ......................305
Block heater .................................................................... 251BRAKE ASSIST -
malfunction and warning messages ..................... 306
Brake assist system (BAS) ............................................ 271
Brake fluid ..................................244, 293, 298, 394, 396
BRAKE FLUID -
malfunction and warning messages ..................... 307
BRAKE LINING WEAR -
malfunction and warning messages ..................... 307
Brake pad wear .............................................................. 307
Brake warning lamp ..................................................... 298
Brake fluid low ......................................................... 298
Brakes ........................................... 242, 244, 271, 272, 274
CCapacities
Fuels, coolants, lubricants etc. .............................. 394
Card, KEYLESS-GO ..........................................................28
Catalytic converter ........................................................ 224
Center console .................................................................. 24
Center console lighting ................................................. 189
Central locking switch .................................................... 50
Central locking system .................................................... 34
Automatic central locking .........................................52
Choosing global or selective mode .....................37, 43
Electronic main key .................................................... 29

409 Index
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car careIndex Standing lamps ........................................ 156, 359, 360
Stop lamps .................................................................. 361
Taillamps .......................................... 156, 312, 360, 377
Turn signal lamps ................................... 358, 360, 361
Level control system
Vehicles with Active Body Control
(ABC) ......................................................................280
Vehicles with Airmatic system ...............................279
LIGHT SENSOR -
malfunction and warning messages ...................... 314
Lighter .............................................................................203
LIGHTING SYSTEM -
malfunction and warning messages ...................... 312
Limp home mode
(Automatic transmission) ........................................ 241
Locking and unlocking ............................................ 36, 40
Lumbar support ............................................................... 73
MMaintenance ................................................................... 213
Malfunction and indicator lamps
In the center console ................................................302
In the instrument cluster .........................................296
Malfunction and warning message memory ............. 136
Malfunction and warning messagesACTIVE BODY CONTROL (ABC) ............................. 314
AIR SPRING (AirMatic) ........................................... 325
BATTERY/ALTERNATOR ......................................... 305
BRAKE ASSIST ......................................................... 306
BRAKE FLUID ........................................................... 307
BRAKE LINING WEAR ............................................ 307
CHIP-CARD (KEYLESS-GO) .................................... 322
COOLANT (coolant level) ......................................... 310
COOLANT (coolant temperature) ........................... 311
CRUISE CONTROL .................................................... 319
DISPLAY DEFECTIVE
(engine control unit) ........................................... 304
DISPLAY DEFECTIVE
(several systems) ................................................. 304
DISTRONIC (DTR) .................................................... 326
DOOR .......................................................................... 320
ELEC. STABIL. PROG. .............................................. 309
ENGINE OIL LEVEL .................................................. 318
ENTRANCE POSITION ............................................ 306
HOOD ......................................................................... 320
KEY .............................................................................. 319
LIGHT SENSOR .......................................................... 314
LIGHTING SYSTEM ................................................... 312
OIL TEMP. (engine oil temperature) ......................321
PARKING BRAKE ..................................................... 308
SELECTOR LEVER .................................................... 323

412 Index
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car careIndex
Remote control .......................................................... 28, 34
Battery replacement .................................................363
Removal and installation of
front seat head restraints .......................................... 72
Replacing bulbs ..............................................................356
Replacing wiper blades .................................................370
Reporting Safety Defects ................................................ 15
Reserve key ....................................................................... 30
Residual engine heat utilization (REST) .................... 174
Roadside assistance ......................................................... 10
Roadside assistance call
See Tele Aid ............................................................... 214
Roof rack ......................................................................... 371
SSeat belts ........................................................................... 84
Fastening ...................................................................... 87
Operation ..................................................................... 88
Seat belt nonusage warning system ........................ 85
Unfastening .................................................................. 88
Warning lamp ............................................................302
Seat belts and integrated restraint system .................. 84
Seat heater ........................................................................ 75
Seat ventilation system ................................................... 78Seats
Front seat adjustment ................................................67
Lumbar support ........................................................... 73
Multicontour backrest ................................................73
Seat heater ...................................................................75
Ventilation system ...................................................... 78
SELECTOR LEVER -
malfunction and warning messages ..................... 323
Service indicator
See Flexible service system (FSS) .......................... 147
Setting the audio volume ..............................................146
Side impact airbags .........................................................96
Simultaneous .................................................................... 44
Simultaneous use of
electronic main key and
KEYLESS-GO-card .......................................................44
Sliding/pop-up roof ........................................................ 184
Emergency operation .............................................. 369
Express opening ........................................................ 185
Opening and closing ...................................................45
Synchronizing ........................................................... 186
Snow chains ................................................................... 249
SOS-call
See Tele Aid ............................................................... 214
Spare parts service ....................................................... 384
Spare wheel ....................................................................341