2005 MERCEDES-BENZ C320 engine

303 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
;
(USA only)
3
(Canada only)
The red brake warning lamp
comes on while driving and
you hear a warning sound.
You are driving with the
parking brake set.

Release the parking brake
(page 48).
The red brake warning lamp
comes on while driving.
There is insufficient brake fluid
in the reservoir.

Risk of accident! Carefully 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 the brake warning lamp illumi-
nated can result in an accident. Have your
brake system checked immediately if the
brake warning lamp stays on. Don’t add
brake fluid before checking the brake
system. Overfilling the brake fluid reservoir
can result in spilling brake fluid on hot
engine parts and the brake fluid catching
fire. You can be seriously 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.

304 Practical hintsWhat to do if …Problem
Possible cause
Suggested solution
ú
(USA only)
±
(Canada only)
The yellow 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
parking brake pedal.

305 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
ú
(USA only)
±
(Canada only)
The yellow engine malfunction
indicator lamp comes on while
driving.
A loss of pressure has been
detected in the fuel system.
The fuel cap may not be closed
properly or the fuel system
may be leaky.

Check the fuel cap (
page 275).
If it is not closed properly:

Close the fuel cap.
If it is closed properly:

Have the fuel system checked by an
authorized Mercedes-Benz Center.
Your fuel tank is empty.

After refuelling start, turn off and
restart the engine three or four times
in succession.
The limp-home mode is canceled. You do
not need to have your vehicle checked.

307 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
The yellow fuel tank reserve warning lamp in the
fuel gauge comes on while driving.
The fuel level has gone below the reserve
mark.

Refuel at the next gas station
(page 275).
<
The red seat belt telltale illuminates
for a brief period after starting the
engine.
The telltale reminds you to fasten seat
belts.

Fasten your seat belt.
The telltale goes out.
1
The red SRS indicator lamp comes on
while driving.
There is a malfunction in the restraint
systems. The air bags or emergency ten-
sioning device (ETDs) could deploy unex-
pectedly or fail to activate in an accident.

Drive with added caution to the
nearest authorized Mercedes-Benz
Center.
Warning!
G
In the event a malfunction of the SRS is
indicated as outlined above, the SRS may
not be operational. For your safety, we
strongly recommend that you visit an autho-
rized Mercedes-Benz Center immediately to
have the system checked; otherwise the
SRS may not be activated when needed in
an accident, which could result in serious or
fatal injury, or it might deploy unexpectedly
and unnecessarily which could result in an
accident and/or injury to you or to others.

314 Practical hintsWhat to do if …Symbol messagesDisplay symbol
Display message
Possible cause
Possible solution
#
Battery Alternator
Visit workshop.
The battery is no longer charging.
Possible causes:

broken poly-V-belt


alternator malfunctioning

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.
Low voltage
Charge battery
The battery has insufficient voltage.

Start the engine (
page 46).
Low voltage
Switch off consumers
The battery has insufficient voltage.

Turn off unnecessary electrical
consumers.

315 Practical hints
What to do if …
Display symbol
Display message
Possible cause
Possible solution
;
(USA only)
!
(Canada only)
Parking brake
Release brake.
You are driving with the parking brake
set.

Release the parking brake
(page 48).
2
Brake wear
Visit workshop.
The brake pads have reached their wear
limit.

Have the brake pads replaced as soon
as possible.
3
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
result in an accident. Have your brake
system checked immediately. Do not add
brake fluid before checking the brake
system. Overfilling the brake fluid reservoir
can result in spilling brake fluid on hot
engine parts and the brake fluid catching
fire. You can be seriously 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 technician at the
intervals specified in the Maintenance
booklet.

316 Practical hintsWhat to do if …Display symbol
Display message
Possible cause
Possible solution
B
Coolant
Check level
The coolant level is too low.

Add coolant (
page 283).

If you have to add coolant frequently,
have the cooling system checked by
an authorized Mercedes-Benz Center.
Warning!
G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You can be seriously burned.
!Do not ignore the low engine coolant
level warning. Extended driving with
the message and symbol displayed
may cause serious engine damage not
covered by the Mercedes-Benz Limited
Warranty.
Do not drive without sufficient amount
of coolant in the cooling system. The
engine will overheat causing major
engine damage.

317 Practical hints
What to do if …
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbol
Display message
Possible cause
Possible solution
•
Coolant
Stop, engine off!
The coolant is too hot.

Stop the vehicle and turn off the
engine.

Only start the engine again after the
message disappears. You could
otherwise damage the engine.
Warning!
G
Driving when your engine is badly over-
heated can cause some fluids which may
have leaked into the engine compartment to
catch fire. You could be seriously burned.
Steam from an overheated engine can cause
serious burns and can occur just by opening
the hood. Stay away from the engine if you
see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.
!The engine should not be operated with
the coolant temperature above 248°F
(120°C). Doing so may cause serious
engine damage which is not covered by
the Mercedes-Benz Limited Warranty.