Page 331 of 430

328 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
CHIP-CARD (KEYLESS-GO)
* C = Category, see page 309.1 Check battery of KEYLESS-GO-card, see page 374.
2 The KEYLESS-GO-card cannot be recognized by the running
engine (e.g. strong radio-frequency interference) or the card is not
in the vehicle.
Stop immediately and search for the KEYLESS-GO-card or continue
to operate the vehicle with the electronic key, otherwise the vehicle
cannot be centrally locked or the engine started again after the
engine stops automatically. See page 36.
3 The KEYLESS-GO-card was momentarily not recognized. If
message repeats, place card in a different position or continue to
operate the vehicle with the electronic key, see page 36.
4 A KEYLESS-GO-card left inside the vehicle has been recognized
while locking the vehicle from the outside, see page 36.
5 The message appears for maximum of 60 seconds each time the
driver’s door is opened, as long as no electronic key is in the
starter switch. The message appears regardless of the past
operation method (electronic key or KEYLESS-GO-card), see
page 36. Line 1 Line 2 C*
CHIP CARD CHECK BATTERY
1
2
CHIP CARD NOT RECOGNIZED!
2
1
CHIP CARD NOT RECOGNIZED!
3
2
CHIP CARD STILL IN VEHICLE
4
1
CHIP CARD DO NOT FORGET!
5
1
Page 332 of 430
329 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index SELECTOR LEVER
(Vehicles with KEYLESS-GO only)
Place selector lever in position “P”.
The message appears when attempting to turn off the
engine while the selector lever is in any other position
than “P”, see page 236.TELEPHONE – FUNCTION
* C = Category, see page 309.The display appears if button í or ì on the
multifunction steering wheel is pressed and the vehicle
is not equipped with a telephone.Line 1 Line 2 C*
FUNCTION NOT AVAILABLE! 3
Page 338 of 430

335 Contents – Practical hints
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index
Practical hintsFirst aid kit .....................................336
Stowing things in the vehicle ......336
Fuses ................................................337
Hood .................................................339
Checking engine oil level .............342
Automatic transmission
fluid level ...................................343
Active body control (ABC)
fluid level ...................................343
Coolant level ...................................344
Adding coolant ...........................344
Windshield and headlamp
washer system ...........................345
Windshield and headlamp
washer fluid mixing ratio .........345Spare wheel, vehicle tools,
storage compartment ............... 346
Vehicle jack .................................... 347
Wheels ............................................ 348
Tire Replacement ....................... 348
Rotating wheels ......................... 349
Spare wheel .................................... 349
Changing wheels ........................... 351
Tire inflation pressure ................. 356
Battery ............................................. 357
Jump starting ................................. 359
Towing the vehicle ........................ 361
Exterior lamps ............................... 364
Headlamp assembly .................. 365
Taillamp assemblies .................. 368Changing batteries in
the electronic key ..................... 371
Synchronizing
remote control ............................373
Changing batteries in the
KEYLESS-GO-card ..................... 374
Emergency engine
shut-down .................................. 376
Fuel filler flap,
manual release .......................... 376
Emergency operation of
sliding/pop-up roof ...................377
Replacing wiper blades .................378
Roof rack .........................................380
Page 361 of 430

358 Battery
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index
Therefore, we strongly recommend that you have the
battery charge checked frequently, and corrected if
necessary, especially if you use the vehicle less than
approximately 200 miles (300 km) per month,
mostly for short distance trips, or if it is not used for
long periods of time.
Only charge a battery with a battery charger after the
battery has been disconnected from the vehicle’s
electrical circuit.
Always disconnect the battery negative lead first and
connect last.
When removing and connecting the battery, always
make sure that all electrical consumers are off and the
electronic key is in starter switch position 0. The
battery, its filler caps, the vent tube and the opposite
plug must always be securely installed when the vehicle
is in operation.
While the engine is running the battery terminal clamps
must not be loosened or detached, otherwise the
generator and other electronic components would be
damaged.Note:
The gear selector lever will remain locked in
position “P” and the electronic key cannot be turned in
the starter switch, if the vehicle battery disconnected or
discharged.
After reconnecting the battery also set the clock (see
COMAND operator’s manual) resynchronize the front
seat head restraints, the express feature of the power
windows, the sliding / pop-up roof, and the electronic
stability program (see head restraints on page 68, power
windows on page 184, sliding/pop-up roof on page 189,
and electronic stability program on page 280).
Battery recycling
Batteries contain materials that can harm the
environment with improper disposal.
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.
Page 364 of 430

361 Towing the vehicle
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index Towing the vehicleImportant!
When towing the vehicle, please, note the following:
With the automatic central locking activated and the
electronic key in starter switch position 2 (vehicles with
KEYLESS-GO: in “On” position, see page 232), the
vehicle 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 door locks from locking,
deactivate the automatic central locking. See
“VEHICLE” under “Individual settings” on page 146.
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.
Note:
The selector lever will remain locked in position “P” and
the electronic key cannot be turned in the starter switch
if the battery is disconnected or discharged. See battery
on page 357 or jump starting on page 359.
Wa r n i n g !
Prior to towing the vehicle with all wheels on the
ground, make certain that the electronic key is in
starter switch position 2. The maximum towing
speed and distance with the vehicle on the ground
is 30 mph (50 km/h) and 30 miles (50 km).If the electronic key is left in the starter switch
position 0 for an extended period of time, it can no
longer be turned in the switch. To unlock, remove
electronic key from starter switch and reinsert.
Page 366 of 430

363 Towing the vehicle
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index We recommend that the vehicle be transported using
flat bed equipment. This method is preferable to other
types of towing.
Important!
To prevent damage during transport, do not tie down
vehicle by its chassis or suspension parts.
The vehicle may be towed with all wheels on the ground
and the selector lever in position “N” for distances up to
30 miles (50 km) and at a speed not to exceed 30 mph
(50 km / h). The electronic key must be in starter switch
position 2.
To be certain to avoid a possibility of damage to the
transmission, however, we recommend the drive shaft
be disconnected at the rear axle drive flange for any
towing beyond a short tow to a nearby garage.
Do not tow with sling-type equipment. Towing with
sling-type equipment over bumpy roads will damage
radiator and supports.
Use wheel lift, dolly, or flat bed equipment, with
electronic key in starter switch turned to position 0.Note:
To signal turns while being towed with hazard warning
flasher in use, turn electronic key in starter switch to
position 2 and activate combination switch for left or
right turn signal in usual manner – only the selected
turn signal will operate.
Upon canceling the turn signal, the hazard warning
flasher will operate again.
Caution!
If the vehicle is towed with the front axle raised, the
engine must be shut off (electronic key in starter switch
position 0 or 1). Otherwise, the ESP will immediately be
engaged and will apply the rear wheel brakes.
Switch off the tow-away alarm (see page 61), the
automatic central locking, see individual setting menu
“VEHICLE” – “AUTOMATIC DOOR LOCK” (see
page 146) as well as the ESP (see page 280).
Wa r n i n g !
With the engine not running, there is no power
assistance for the braking and steering systems. 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.
Page 374 of 430
371 Electronic key
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index Changing batteries in the electronic key
1Transmit buttons
2Lamp for battery check and function control
Checking batteries
If one of the transmit buttons (1) is pressed, the battery
check lamp (2) lights up briefly – indicating that the
batteries are in order.
Change batteries if the battery check lamp (2) does not
light up briefly.Changing batteries
Move locking tab (3) in direction of right arrow and
remove mechanical key (4, left arrow).
P80.20-2201-26
1
2
P80.35-2029-26
4
3
Page 375 of 430
372 Electronic key
Te ch n i c a 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
key.
P80.35-2025-26
5
4
6
P80.35-2027-26
78