2003 MERCEDES-BENZ C320 COUPE check engine

148 Controls in detailClimate controlAir conditioning
The air conditioning is operational while
the engine is running and cools the interior
air to the temperature set by the operator.
Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the climate
control system. The air in the vehicle will
then no longer be cooled or dehumidified.
Press buttonAC
OFF
(page 143).
The indicator lamp on the
buttonAC
OFF
lights up.Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.

PressAC
OFF
again (
page 143).
The indicator lamp on the
buttonAC
OFF
goes out.
The air conditioning system uses the refrig-
erant R134a. This refrigerant is free of
CFCs which are harmful to the ozone layer.
Ventilated storage compartment
The front center console storage compart-
ment has its own air vent that allows for
cooling ventilation when the climate con-
trol system is activated.
1Lever
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.
!If the air conditioning cannot be turned
on again, this indicates that the air con-
ditioning system is losing refrigerant.
The compressor has turned itself off.
Have the air conditioning system
checked at the nearest authorized
Mercedes-Benz Center.
iYou should keep this air vent closed
when outside temperatures are low.

157 Controls in detail
Automatic climate control* (Canada only)
Air conditioning
The air conditioning is operational while
the engine is running and cools the interior
air to the temperature set by the operator.
Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the automatic
climate control system. The air in the vehi-
cle will then no longer be cooled or dehu-
midified.
Press buttonAC
OFF
(page 151).
The indicator lamp on the
buttonAC
OFF
lights up.Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.

PressAC
OFF
again (
page 151).
The indicator lamp on the
buttonAC
OFF
goes out.
The air conditioning system uses the refrig-
erant R134a. This refrigerant is free of
CFCs which are harmful to the ozone layer.
Warning!
G
Any accumulation of snow and ice should be
removed from the rear window before driv-
ing. Visibility could otherwise be impaired,
endangering you and others.!If the rear window defroster switches
off too soon and the indicator lamp
starts blinking, this means that too
many electrical consumers are operat-
ing simultaneously and there is insuffi-
cient voltage in the battery. The system
responds automatically by deactivating
the rear window defroster.
As soon as the battery has sufficient
voltage, the rear window defroster au-
tomatically turns itself back on.
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.
!If the air conditioning cannot be turned
on again, this indicates that the air con-
ditioning system is losing refrigerant.
The compressor has turned itself off.
Have the air conditioning system
checked at the nearest authorized
Mercedes-Benz Center.

216 OperationDriving instructionsPower assistanceBrakesTo 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. If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on, the brake fluid level in the res-
ervoir is too low.
Brake pad wear or a leak in the system may
be the reason for low brake fluid in the res-
ervoir.
Have the brake system inspected at an au-
thorized Mercedes-Benz Center immedi-
ately.
All checks and service work on the brake
system should be carried out by an autho-
rized Mercedes-Benz Center.
Install only brake pads and brake fluid rec-
ommended by Mercedes-Benz.Warning!
G
When the engine is not running, the brake
and steering systems are without power as-
sistance. Under these circumstances, a
much greater effort is necessary to stop or
steer the vehicleWarning!
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 ef-
fect. 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 acci-
dent.
!Be very careful not to endanger other
road users when you apply the brakes.
Refer to the description of the Brake
Assist System (BAS) (
page 74).

225 Operation
At the gas station
Check regularly and before a long trip
1Coolant level
More information on the coolant level
can be found in the “Operation” section
(
page 229).
2Brake fluid (fuse box cover removed)
More information on brake fluid can be
found in the “Technical data” section
(page 317).
Removing fuse box cover see page
(page 303).
3Windshield washer and headlamp
cleaning system
For more information on refilling the
reservoir, see the “Operation” section
(page 232).Engine oil level
More information on engine oil can be
found in the “Operation” section
(
page 227).
Opening hood see (
page 226).
Coolant
For normal replenishing, use water (pota-
ble water quality). More information on
coolant can be found in the“Operation”
section (
page 229).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
the “Practical hints” section (
page 280).
Exterior lamp switch (
page 96).
Tire inflation pressure
More information on tire inflation pressure
can be found in the “Operation” section
(
page 234).
iUse only premium unleaded gasoline
with a minimum Posted Octane Rating
of 91 (average of 96 RON / 86 MON).
Information on gasoline quality can
normally be found on the fuel pump.
More information on gasoline can be
found in the Factory Approved Service
Products pamphlet.iLeaving the engine running and the fuel
cap open can cause the
?
lamp to
illuminate.
More information can be found in the
“Practical hints” section (
page 250).

227 Operation
Engine compartment
Closing
Let the hood drop from a height of ap-
proximately 1ft (30cm).
The hood will lock audibly.

Check to make sure that the hood is
fully closed.
If you can raise the hood at a point
above the headlamps, then it is not
properly closed. Open it again and let it
drop with somewhat greater force.
Engine oil
The amount of oil your engine needs will
depend on a number of factors, including
driving style. Higher oil consumption can
occur when

the vehicle is new


the vehicle is driven frequently at high-
er engine speeds
Engine oil consumption checks should only
be made after the vehicle break-in period.
Checking engine oil level
When checking the oil level the vehicle
must


be parked on level ground


be at normal operating temperature


have been stationary for at least five
minutes with the engine turned off
Warning!
G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature gauge indicates that the engine is
overheated, do not open the hood. Move
away from vehicle and do not open the hood
until the engine has cooled. If necessary,
call the fire department.Warning!
G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components (ig-
nition coils, spark plug sockets, diagnostic
socket) of the ignition system

with the engine running


while starting the engine


if ignition is “on” and the engine is
turned manually
Warning!
G
Be careful that you do not close the hood on
anyone.

228 OperationEngine compartmentYou can check the engine oil level on the
multifunction display.
Turn the key in the starter switch to
position2.
The standard display showing the trip
odometer and the main odometer
(
page 105) should appear in the multi-
function display.

Press button
k
or
j
, on the
steering wheel until the following mes-
sage is seen in the multifunction dis-
play:
ENGINE OIL LEVEL - MEASUREMENT IN
PROCESS!
CORRECT MEASUREMENT ONLY
IF VEH. LEVEL
After about three seconds this mes-
sage is displayed:ENGINE OIL LEVEL-MEASURING NOWOne of the following messages will sub-
sequently appear in the indicator:

ENGINE OIL LEVEL - O.K.



ENGINE OIL LEVEL - ADD 1 QUART
(1.o LITER)!


ENGINE OIL LEVEL - ADD 1.5
QUARTS (1.5 LITERS)!


ENGINE OIL LEVEL - ADD 2.0
QUARTS (2.0 LITERS)!
Adding engine oil
1Filler neck
Unscrew the cap from filler neck 1. Be
careful not to overfill with oil.
Be careful not to spill any oil when adding.
Avoid environmental damage caused by oil
entering the ground or water.!Excessive oil must be siphoned or
drained off. It could cause damage to
the engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.


229 Operation
Engine compartment

Screw the cap back on the filler neck.
Other display messages
If there is excessive engine oil with the en-
gine at normal operating temperature, the
following message will appear:
ENGINE OIL LEVEL - REDUCE OIL LEVEL
Have excess oil siphoned.
If the key is not turned to position 2 in the
starter switch:
FOR ENGINE OIL LEVEL IGNITION ON
PLEASE!
Switch on the ignition.
If you see the message:
OBSERVE WAITING PERIOD
Wait five minutes before repeating
check procedure.
If you see the message:
ENGINE OIL LEVEL - NOT WHEN ENGINE ON!
Turn off the engine. If engine is at nor-
mal operating temperature, wait five
minutes before checking oil. If the en-gine is not yet at normal operating tem-
perature, you must wait 30 minutes
before checking oil.
If a proper oil level check cannot be per-
formed, the following message will appear:
ENGINE OIL LEVEL - MASURING NOT POS-
SIBLE
Repeat the engine oil level check after
a short while.
See “Practical hints” (
page 262) if an en-
gine oil level indicator appears on the dis-
play when the engine is running.
More information on engine oil can be
found in the “Technical data” section
(
page 317).
Transmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Center
check the transmission.Coolant level
The engine coolant is a mixture of water
and anticorrosion/antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
The coolant expansion tank is located on
the passenger side of the engine compart-
ment.

231 Operation
Engine compartment
Battery
Your vehicle’s battery is located in the en-
gine compartment on the right hand side.
The battery should always be sufficiently
charged in order to achieve its rated ser-
vice life.
If you use your vehicle mostly for short dis-
tance trips, you will need to have the bat-
tery charge checked more frequently.
When replacing the battery, always use
batteries approved by Mercedes-Benz.
If you do not intend to operate your vehicle
for an extended period of time, consult an
authorized Mercedes-Benz Center about
steps you need to observe.Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
G
Observe all safety instructions
and precautions when handling
automotive batteries.
A
Risk of explosion.
D
Keep flames or sparks away
from battery. Do not smoke.
B
Battery acid is caustic. Do not
allow it to come into contact
with skin, eyes or clothing.
In case it does, immediately
flush affected area with clear
water and seek medical help if
necessary.
E
Wear eye protection.
C
Keep children away.
F
Follow the instructions in this
Operator's Manual.