2008 MERCEDES-BENZ C300 Keyless start

312 Operation
Driving instructions
Brakes
To help prevent brake disk corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes.
If your brake system is normally only sub-
jected to moderate loads, you should occa-
sionally test the effectiveness of the brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.
Refer to the description of the Brake Assist
System (BAS) (
page 60).
Brake pad wear or a leak in the system may
be the reason for low brake fluid level in
the reservoir.
The brake fluid level in the reservoir may
be too low if the red brake warning lamp in
the instrument cluster comes on while the
engine is running and an acoustic warning
sounds (
page 376). Observe additional
messages in the multifunction display that
may appear (
page 387).
Warning!G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking
effect. Maintain a safe distance from
vehicles in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an
accident.
!Vehicles without 4MATIC:
Because the ESP® operates automatically, the
engine and ignition must be shut off (SmartKey
in starter switch position0 or1 or KEYLESS-GO
(Canada only) start/stop button* in position0
or1) when

the parking brake is being tested on a brake
test dynamometer

the vehicle is being towed with the front axle
raised
Active braking action through the ESP
® may oth-
erwise seriously damage the brake system.
For information on vehicles with 4MATIC, see
“Four wheel electronic traction system (4MATIC)
with the ESP®” (
page 65).
Warning!G
Make sure not to endanger any other road
users when carrying out these braking ma-
neuvers.

314 Operation
Driving instructions
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine smoothly. Do not
place full load on the engine until the oper-
ating temperature has been reached.Parking
!When driving off on a slippery surface, do
not allow a drive wheel to spin for an extended
period with the ESP
® switched off. Doing so may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited War-
ranty.
!Simultaneously depressing the accelerator
pedal and applying the brakes reduces engine
performance and causes premature brake and
drivetrain wear.
Warning!G
Do not park this vehicle in areas where
combustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
To reduce the risk of personal injury, or
damage to the vehicle or the vehicle
drivetrain, as a result of vehicle movement,
always do the following before turning off
the engine and leaving the vehicle:

Keep right foot on brake pedal.

Manual transmission: Move the gear
shift lever to neutral position (no gear
selected).

Firmly depress the parking brake.

Manual transmission: Move the gear
shift lever into first or reverse gear.

Automatic transmission*: Move the
gear selector lever to positionP.

Slowly release brake pedal.

When parked on an incline, turn front
wheels towards the road curb.

Turn the SmartKey or the SmartKey
with KEYLESS-GO* (Canada only) to
starter switch position0 and remove, or
press the KEYLESS-GO* start/stop but-
ton.

Take the SmartKey or the SmartKey with
KEYLESS-GO
* with you and lock the
vehicle when leaving.

323 Operation
At the gas station
Turn off the engine.
Vehicles with automatic transmission*:
Move the gear selector lever to
positionP (
page 140).
Remove the SmartKey from the starter
switch.
Vehicles with SmartKey with
KEYLESS-GO*:
Turn off the engine by pressing the
KEYLESS-GO* button once.
Open the driver’s door (this puts
the starter switch in position0,
same as with the SmartKey re-
moved from the starter switch). The
driver’s door then can be closed
again.
Open the fuel filler flap by pushing at
the point indicated by arrow 1.The fuel filler flap springs open.
Turn the fuel cap counterclockwise and
hold on to it until possible pressure is
released.
Take off the fuel filler cap and set it in
the direction of arrow 2 and place it
into holder 4 located on the inside of
the fuel filler flap.
To prevent fuel vapors from escaping
into open air, fully insert filler nozzle
unit.
Only fill your tank until the filler nozzle
unit cuts out – do not top off or over-
fill.
Replace the fuel cap by turning it clock-
wise until it audibly engages.
Close the fuel filler flap.
You should hear the latch close shut.
For more information on gasoline or E85, see
“Premium unleaded gasoline” (
page 481) or
the Factory Approved Service Products
pamphlet (USA only) in your vehicle literature
portfolio, or contact an authorized
Mercedes-Benz Center.
Warning!G
Overfilling of the fuel tank may create pres-
sure in the system which could cause a gas
discharge. This could cause the gas to spray
back out when removing the fuel pump noz-
zle, which could cause personal injury.
iMake sure to close the fuel filler flap before
locking your vehicle as the flap locking pin pre-
vents closing after you have locked the vehicle.
iLeaving the engine running and the fuel cap
open can cause the yellow engine malfunction
indicator lamp ± to illuminate.
For more information, see the “Practical hints”
section (
page 378).

368 Operation
Vehicle care
Cleaning the windows and the wiper
blades
Make sure the hood is fully closed.
Placing wiper arms in vertical position
Vehicles with SmartKey:
Turn SmartKey in starter switch
position1.
Turn combination switch to wiper
settingu (
page 117).
With wiper arm in vertical position, turn
the SmartKey in starter switch to
position0.Vehicles with KEYLESS-GO*
(Canada only):
Make sure the vehicle’s on-board elec-
tronics have status 1 (
page 84).
Turn combination switch to wiper
settingu (
page 117).
Press KEYLESS-GO start/stop button
repeatedly until windshield wipers
start.
Press KEYLESS-GO start/stop button
when the wiper arms are in a vertical
position.Cleaning
Fold the wiper arms forward until they
snap into place.
Clean the wiper blade inserts with a
clean cloth and detergent solution.
Use a soft, clean cloth and a mild win-
dow cleaning solution on all outside
and inside glass surfaces.
An automotive glass cleaner is recom-
mended.
!The windshield wipers must be in a vertical
position before folding them away from the wind-
shield. They could otherwise damage the hood.
Never open the hood when the wiper arms are
folded forward.Warning!G
For safety reasons, switch off wipers and re-
move SmartKey from starter switch (vehi-
cles with KEYLESS-GO* (Canada only):
Make sure the vehicle’s on-board electron-
ics have status0) before cleaning the wind-
shield and/or the wiper blades. Otherwise,
the wiper motor could suddenly turn on and
cause injury.
!Do not pull on the wiper blade inserts. They
could tear.

369 Operation
Vehicle care
Cleaning the panorama roof with
tilt/sliding panel*
The rear part of the tilt/sliding panel has a
protective layer on the inside.
Use a soft, clean cloth and a mild
window cleaning solution.
An automotive glass cleaner is recom-
mended.Chrome-plated exhaust tip*
Regular cleaning and care of chrome-plat-
ed exhaust tips will help to maintain their
shine and the classy appearance.Use Mercedes-Benz approved Chrome
Polishing Paste each time the vehicle
has been washed, especially during the
winter.
!Fold the windshield wiper arms back onto
the windshield before turning the SmartKey in
the starter switch or pressing the KEYLESS-GO*
start/stop button (vehicles with KEYLESS-GO*
(Canada only)).
Hold on to the wiper when folding the wiper arm
back. If released, the force of the impact from
the tensioning spring could crack the windshield.
!To clean the window interior, do not use a
dry cloth, abrasives, solvents or cleaners con-
taining solvents. Do not touch the inside of the
front, rear or side windows with hard objects
such as an ice scraper or ring. Doing so may
damage the windows.
!Do not use a dry cloth, abrasives, solvents
or cleaners containing solvents. Do not touch
the protective layer with hard objects such as an
ice scraper or ring. Never apply strong force and
only use a soft, non-scratching cloth when clean-
ing the rear part of the tilt/sliding panel.
Otherwise you may scratch or damage the pro-
tective layer.!Do not use alkaline cleaners such as wheel
cleaners as they could cause corrosion.

392 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
Shift
to PYou have turned off the engine with the
KEYLESS-GO* start/stop button (Canada only) in
gear selector lever positionN and opened the driv-
er’s door.
or
You have attempted to switch off the engine with the
KEYLESS-GO* start/stop button (Canada only) while
the gear selector lever was in positionR orD.Place the gear selector lever in positionP.
Shift to P or N
To Start EngineYou have attempted to start the engine while the au-
tomatic transmission* was set to position R or D.Move the gear selector lever to position P or N
(
page 140).
Tire Press. Monitor
Inoperative
(USA only)
The TPMS is malfunctioning.Have the TPMS checked at an authorized
Mercedes-Benz Center.
Wheel Sensors Error
Tire Pressure Monitor
Inoperative
(USA only)
There are wheels without appropriate wheel sensors
mounted (e.g. winter tires).Have the TPMS checked at an authorized
Mercedes-Benz Center.
Have the wheel sensors installed at an autho-
rized Mercedes-Benz Center.
Tire Press. Monitor
Currently Unavailable
(USA only)
The TPMS is unable to monitor the tire pressure due
to a nearby radio interference source.As soon as the causes of the malfunction have
been removed, the TPMS automatically be-
comes active again after a few minutes driving.

407 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
IKey Not
DetectedThe SmartKey with KEYLESS-GO* (Canada
only) is not recognized while the engine is
running because the SmartKey with
KEYLESS-GO* (Canada only) is not in the
vehicle.Stop the vehicle in a safe location or as soon
as it is safe to do.
Search for the SmartKey.
Otherwise the vehicle cannot be centrally
locked nor can the engine be started again
after the engine is stopped.
The SmartKey with KEYLESS-GO* (Canada
only) is not recognized while the engine is
running because there is strong radio-fre-
quency interference.Stop the vehicle in a safe location or as soon
as it is safe to do.
Remove KEYLESS-GO* button (Canada only)
from the starter switch (
page 83).
Operate the vehicle with the SmartKey in the
starter switch.
IKey
Not DetectedThe SmartKey with KEYLESS-GO* (Canada
only) is momentarily not recognized.Change the position of the SmartKey in the
vehicle.
If necessary, operate vehicle using SmartKey
with KEYLESS-GO* (Canada only) in starter
switch under KEYLESS-GO* button (Canada
only) (
page 83).

408 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
IReplace
Key BatteryThe batteries in the SmartKey with
KEYLESS-GO* are discharged.Replace the batteries (page 428).
Key Detected
In VehicleA SmartKey with KEYLESS-GO* (Canada
only) left in the vehicle was recognized
while locking the vehicle from the outside.Take the SmartKey with KEYLESS-GO* out of
the vehicle.
Obtain
A New KeyThe SmartKey with KEYLESS-GO* (Canada
only) must be replaced.Contact an authorized Mercedes-Benz Cen-
ter as soon as possible.
Remove "Start"
Button
And Insert KeyThe KEYLESS-GO* system (Canada only) is
malfunctioning.Remove KEYLESS-GO* button (Canada only)
from the starter switch (
page 83).
Operate the vehicle with the SmartKey in the
starter switch.
IClose Doors
To Lock VehicleYou wanted to lock the vehicle but not all
doors were closed.Close doors and lock vehicle again.
Key Does Not
Belong to VehicleYou have insert an incorrect key in the start-
er switch.Remove key and insert the correct key.
Don’t Forget
Your KeyThis display appears (for a maximum of
60 seconds) if the driver’s door is opened
with the engine turned off and no SmartKey
in the starter switch.
This message is only a reminder.Take the SmartKey or SmartKey with
KEYLESS-GO* (Canada only) with you when
leaving the vehicle.