2008 MERCEDES-BENZ C300 Check engin

377 Practical hints
What to do if …?
ProblemPossible cause/consequenceSuggested solution
;
(USA only)
3
(Canada only)
The red brake warning
lamp comes on while the
engine is running and an
acoustic warning sounds.You are driving with the parking brake set.Release the parking brake
(
page 130).
The red brake warning
lamp comes on while the
engine is running.There is insufficient brake fluid in the reser-
voir.Risk of accident!
Carefully stop the vehicle in a safe loca-
tion or as soon as it is safe to do so.
Depress the parking brake
(
page 134).
Contact 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.
Do not add brake fluid before checking the
brake system.
Overfilling the brake fluid reservoir can re-
sult 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.

378 Practical hints
What to do if …?
ProblemPossible cause/consequenceSuggested solution
±The yellow engine malfunc-
tion 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 en-
gine to its limp-home (emergency opera-
tion) mode.
Have the vehicle checked as soon as
possible at an authorized
Mercedes-Benz Center.
An on-board diagnostic connector is
used by the service station to link the
vehicle to the shop diagnostics system.
It allows the accurate identification of
system malfunctions through the read-
out of diagnostic trouble codes. It is lo-
cated in the front left area of the
footwell next to the parking brake pedal.
iIn some states you may be required by law
to have the vehicle serviced as soon as the
engine malfunction indicator lamp comes on.
Check local requirements.

379 Practical hints
What to do if …?
ProblemPossible cause/consequenceSuggested solution
±The yellow engine malfunc-
tion 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.
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked at an au-
thorized Mercedes-Benz Center.
vThe yellow ESP® warning
lamp comes on while the
engine is running.The ESP® has been switched off with the
ESP® switch or has been switched off due
to a malfunction.
Risk of accident!
When the ESP
® is switched off it will not
stabilize the vehicle if the system recogniz-
es that the vehicle starts to skid or that a
wheel is spinning.
The cruise control is deactivated and can-
not be switched on.
Switch the ESP® back on (page 64).
Exceptions: (
page 63).
If leaving the ESP® switched off, adapt
your speed and driving to the prevailing
road, weather and traffic conditions.
If the ESP
® cannot be switched on:
Continue driving with added caution.
Observer additional messages that may
appear in the multifunction display
(
page 389).
Have the system checked at an
authorized Mercedes-Benz Center as
soon as possible.

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.

400 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
;Check
Brake Fluid LevelThere is insufficient brake fluid in the reser-
voir.Risk of accident!
Carefully stop the vehicle in a safe location or
as soon as it is safe to do so.
Depress the parking brake (page 134).
Contact an authorized Mercedes-Benz Cen-
ter.
Do not add brake fluid! This will not solve the
problem.
(USA only)
3
(Canada only)
Warning!G
Driving with the message Check Brake
Fluid Level
displayed can result in an ac-
cident. Have your brake system checked im-
mediately. 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 serious-
ly 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.

403 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
•Coolant Low
Stop Vehicle!
Turn Engine OffThe poly-V-belt could be broken.Stop the vehicle in a safe location or as soon
a s it is sa fe t o do so and im media tely turn off
the engine.
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise the en-
gine will overheat due to an inoperative water
pump which may result in damage to the en-
gine.
Notify an authorized Mercedes-Benz Center.
If it is intact:
Do not continue to drive the vehicle with this
message displayed. Doing so could result in
serious engine damage that is not covered by
the Mercedes-Benz Limited Warranty.
Observe the coolant temperature gauge in
the instrument cluster (
page 26).
(Continued on next page)

405 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
BCheck
Coolant Level
See Operator’s Manu-
alThe coolant level is too low.Add coolant (page 329).
If you have to add coolant frequently, have
the cooling system checked at an autho-
rized 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 could 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 Lim-
ited Warranty.
Do not drive without a sufficient amount of cool-
ant in the cooling system. The engine will over-
heat, causing major engine damage.

415 Practical hints
What to do if …?
When the message Check Engine Oil At
Next Refueling
appears while the engine
is running and at operating temperature,
the engine oil level has dropped to approx-
imately the minimum level.
When this occurs, the warning will first
come on intermittently and then stay on if
the oil level drops further.
Visually check for oil leaks. If no obvious oil
leaks are noted, continue to drive to the
nearest service station where the engine
oil should be topped to the required level
with an approved oil specified in the Facto-
ry Approved Service Products pamphlet.
For information on approved engine oils,
refer to the Factory Approved Service
Products pamphlet (USA only) or contact
an authorized Mercedes-Benz Center.
Display Possible cause/consequencePossible solution
ùCheck
Engine Oil
At Next RefuelingThe engine oil level has dropped to approx-
imately the minimum level.Check the engine oil level (page 327) and
add engine oil as required (
page 328).
If you must add engine oil frequently, have
the engine checked for possible leaks.
!The engine oil level warnings should not be
ignored. Extended driving with the symbol dis-
played could result in serious engine damage
that is not covered by the Mercedes-Benz Limit-
ed Warranty.