check engine MERCEDES-BENZ C320 2003 W203 User Guide

224 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
subject to moderate loads, you should
occasionally 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.
Only install brake pads and brake fluid
recommended 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).

234 OperationAt 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 238).
2Brake fluid (fuse box cover removed)
More information on brake fluid can be
found in the “Technical data” section
(page 332).
Removing fuse box cover
(page 312).
3Windshield washer and headlamp
cleaning system*
For more information on refilling the
reservoir, see the “Operation” section
(page 241).Engine oil level
More information on engine oil can be
found in the “Operation” section
(
page 236).
Opening hood (
page 235).
Coolant
For normal replenishing, use water (pota-
ble water quality). More information on
coolant can be found in the “Operation”
section (
page 238).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
the “Practical hints” section (
page 290).
Exterior lamp switch (
page 101).
Tire inflation pressure
More information on tire inflation pressure
can be found in the “Operation” section
(
page 243).
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.
Flexible Fuel Vehicles (MY 2003
Mercedes-Benz C 320 models, except
those equipped with manual transmis-
sion or 4MATIC*):
More information on Flexible Fuel Vehi-
cles can be found in the “Technical da-
ta” section (
page 334).
iLeaving the engine running and the fuel
cap open can cause the
?
lamp to
illuminate.
See also “Practical hints” section
(
page 259).

236 OperationEngine 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
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.

237 Operation
Engine compartment
You can check the engine oil level on the
multifunction display.
Turn the key in the starter switch to
position2.
The standard display (
page 116) should
appear in the multifunction 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 – OK



ENGINE OIL LEVEL – ADD
1 QUART (1.0 LITER)!


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


ENGINE OIL LEVEL – ADD
2 QUARTS (2.0 LITERS)!
Adding engine oil
1Filler neck
Unscrew the cap from filler neck1. 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.

Screw the cap back on the filler neck.!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.

238 OperationEngine compartmentOther 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 position2 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:
MEASURING NOT POSSIBLE
Repeat the engine oil level check after
a short while.
See “Practical hints” (
page 270) 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 332).
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.

240 OperationEngine compartmentBattery
Your vehicle’s battery is located in the en-
gine compartment (
page 303).
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.

245 Operation
Winter driving
Winter driving
Before the onset of winter have your vehi-
cle winterized at an authorized
Mercedes-Benz Center. This service in-
cludes:

Check of anticorrosion and antifreeze
concentration.


Addition of cleaning concentrate to the
water of the windshield and headlamp
cleaning system. Add MB Concentrate
“S” to a premixed windshield washer
solvent / antifreeze which is formulated
for below freezing temperatures
(page 338).


Battery test. Battery capacity drops
with decreasing ambient temperature.
A well charged battery helps to ensure
that the engine can be started, even at
low ambient temperatures.


Tire change. We recommend M+S rat-
ed radial-ply tires on all four wheels for
the winter season.
Winter tires
Always use winter tires at temperatures
below 39°F (4°C) and whenever wintry
road conditions prevail. Use of winter tires
is the only way to achieve the maximum ef-
fectiveness of ABS, ESP and 4MATIC* in
winter operation.
For safe handling, ensure that all mounted
winter tires are of the same make and have
the same tread design.Always observe the speed rating of the
winter tires installed on your vehicle. If the
maximum speed for which your tires are
rated is below the speed rating of your ve-
hicle, you must place a notice to this effect
where it will be seen by the driver. Such no-
tices are available from your tire dealer or
from any authorized Mercedes-Benz Cen-
ter.Warning!
G
Winter tires with a tread depth under 0.16 in
(4 mm) must be replaced. They are no long-
er suitable for winter operation.
Warning!
G
If you use your spare tire when winter tires
are fitted on the other wheels, be aware that
the difference in tire characteristics may
very well impair turning stability and that
overall driving stability may be reduced.
Adapt your driving style accordingly.
Have the spare tire replaced with a winter
tire at the nearest authorized
Mercedes-Benz Center.

259 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
?
The yellow “CHECK ENGINE”
malfunction indicator lamp
comes on while driving.
There is a malfunction in:

The fuel management system


The ignition system


The emission control system


Systems which affect emissions
Such malfunctions may result in excessive
emissions values and may switch the engine
to its limp-home (emergency operation)
mode.

Have the vehicle checked as soon as
possible by an authorized
Mercedes-Benz Center.
An on-board diagnostic connector is
used by the service station to link the
vehicle to the shop diagnostics sys-
tem. It allows the accurate identifica-
tion of system malfunctions through
the readout of diagnostic trouble
codes. It is located in the front left
area of the footwell next to the park-
ing brake pedal.
The fuel cap is not closed tight.

Check the fuel cap.
Your gas tank is empty.

After refuelling start the engine three
or four times in succession.
The limp-home mode is canceled. You do
not need to have your vehicle checked.
<
The red seat belt warning lamp
blinks for a brief period after
starting the engine.
The warning lamp reminds you to fasten seat
belts.

Fasten your seat belt.
The yellow fuel tank reserve warning lamp
lights while driving.
The fuel level has gone below the reserve
mark.

Refuel at the next gas station
(page 233).

264 Practical hintsWhat to do if …#
BATTERY/ALTERNATOR
VISIT WORKSHOP!
The battery is no longer charging.
Possible causes:

alternator malfunctioning


broken poly-V-belt

Stop immediately and check the
poly-V-belt.
If it is broken:

Do not continue to drive. Otherwise
the engine will overheat due to an
inoperative water pump which may
result in damage to the engine. Notify
an authorized Mercedes-Benz Center.
If it is intact:

Drive immediately to the nearest
authorized Mercedes-Benz Center.
!
(Canada
only)
;
(USA only)
PARKING BRAKE
RELEASE PARKING BRAKE!
You are driving with the parking brake
set.

Release the parking brake
(page 51).
Display
Possible cause
Suggested solution

265 Practical hints
What to do if …
Display
Possible cause
Suggested solution
3
(Canada
only)
;
(USA only)
BRAKE PAD WEAR
VISIT WORKSHOP!
The brake pads have reached their wear
limit.

Have the brake pads replaced as soon
as possible.
BRAKE FLUID
VISIT WORKSHOP!
There is insufficient brake fluid in the
reservoir.

Risk of accident! Stop the vehicle and
notify an authorized Mercedes-Benz
Center. Do not add brake fluid! This
will not solve the problem.
Warning!
G
Driving with this message displayed can re-
sult in an accident. Have your brake system
checked immediately. Don’t add brake fluid
before checking the brake system. Overfill-
ing the brake fluid reservoir can result in
spilling brake fluid on hot engine parts and
the brake fluid catching fire. You can be se-
riously burned.
!If you find that the brake fluid in the
brake fluid reservoir has fallen to the
minimum mark or below, have the
brake system checked for brake pad
thickness and leaks.
!Brake pad thickness must be visually
checked by a qualified technican at the
intervals specified in the Service
booklet.