2003 MERCEDES-BENZ S CLASS check engine

294 Practical hintsWhat 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 tightly.

Close 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 yellow fuel tank reserve
warning lamp lights up while
driving.
The fuel level has gone below the reserve
mark.

Refuel at the next gas station
(page 261).
<
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.

301 Practical hints
What to do if …?
Display
Possible cause
Suggested solution
#
BATTERY/ALTERNATOR
VISIT WORKSHOP!
The battery was charged with a battery
charger or jump started.

Have the battery checked at a ser-
vice station.
The battery is no longer charging.
Possible causes:

Alternator malfunctioning


Broken poly-V-belt
Do not forget that the brake system re-
quires electrical energy and may be operat-
ing with restricted capability. Considerably
greater brake pedal force is required and
the stopping distance is longer.

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 in-
operative water pump which may re-
sult in damage to the engine. Notify
an authorized Mercedes-Benz
Center.
If it is intact:

Drive immediately to the nearest au-
thorized Mercedes-Benz Center. Ad-
just driving to be consistent with
reduced braking responsiveness.

302 Practical hintsWhat to do if …?Display
Possible cause
Suggested solution
2
BRAKE WEAR
VISIT WORKSHOP!
The brake pads have reached their wear
limit.

Have the brake pads replaced as
soon as possible.
Except Canada:;Canada only:3
BRAKE FLUID
VISIT WORKSHOP!
There is insufficient brake fluid in the reser-
voir.

Risk of accident! Stop the vehicle
and notify an authorized
Mercedes-Benz Center. Do not add
brake fluid! This will not solve the
problem.
!Brake pad thickness must be visually
checked by a qualified technician at the
intervals specified in the Service Book-
let.
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.

303 Practical hints
What to do if …?
Display
Possible cause
Suggested solution
F
CHIP CARD
CHECK BATTERY
KEYLESS-GO*card batteries are dis-
charged.

Change the batteries (
page 328).
CHIP CARD
NOT RECOGNIZED!
KEYLESS-GO*card is not recognized while
the engine is running because

the card is not in the vehicle


there is strong radio-frequency interfer-
ence

Stop the vehicle as soon as it is safe
to do so.

Search for the card.
Otherwise the vehicle cannot be central-
ly locked nor can the engine be started
again after it has been stopped.
KEYLESS-GO*card is momentarily not rec-
ognized.

Change the position of the card in
the vehicle.

Operate the vehicle with the
SmartKey in the ignition if necessary.
CHIP CARD
DETECTED IN VEHICLE
KEYLESS-GO*card left in the vehicle was
recognized while locking the vehicle from
the outside.

Take the card out of the vehicle.
CHIP CARD
VISIT WORKSHOP!
The KEYLESS-GO* system is malfunction-
ing.

Visit an authorized Mercedes-Benz
Center as soon as possible.

304 Practical hintsWhat to do if …?Display
Possible cause
Suggested solution
F
CHIP CARD
DO NOT FORGET
This display appears (for a maximum of
60 seconds) if the driver’s door is opened
with the engine shut off and no SmartKey in
the ignition.
Message is only a reminder.

Insert SmartKey in the ignition.

Take the KEYLESS-GO*card with you
when leaving the vehicle.
B
COOLANT
CHECK LEVEL!
The coolant level is too low.

Add coolant (
page 268).

If you have to add coolant frequently,
have the cooling system checked by
an authorized Mercedes-Benz Cen-
ter.
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 a sufficient
amount of coolant in the cooling sys-
tem. The engine will overheat, causing
major engine damage.

306 Practical hintsWhat to do if …?Display
Possible cause
Suggested solution
Ï
COOLANT
STOP, ENGINE OFF!
The poly-V-belt could be broken.

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 in-
operative water pump which may re-
sult in damage to the engine. 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.
Ï
COOLANT
VISIT WORKSHOP!
The cooling fan for the coolant is malfunc-
tioning.

Observe the coolant temperature
display.

Have the fan replaced as soon as
possible.

308 Practical hintsWhat to do if …?Display
Possible cause
Suggested solution
:
ENGINE OIL LEVEL
STOP, ENGINE OFF!
There is no oil in the engine. There is a dan-
ger of engine damage.

Carefully bring the vehicle to a halt
as soon as possible.

Turn off the engine.

Add engine oil.
ENGINE OIL LEVEL
REDUCE OIL LEVEL
You have added too much engine oil. There
is a risk of damaging the engine or the cat-
alytic converter.

Have oil siphoned. Observe all legal
requirements with respect to its dis-
posal.
ENGINE OIL
VISIT WORKSHOP!
The engine oil has dropped to a critical lev-
el.

Check the engine oil level
(page 264) and add oil as required.

If you must add engine oil frequently,
have the engine checked for possible
leaks.
There is water in the oil.

Have the oil checked.

309 Practical hints
What to do if …?
When the
ENGINE OIL LEVEL – CHECK LEV-
EL!
message appears while the engine is
running and at operating temperature, the
engine oil level has dropped to approxi-
mately the minimum mark on the dipstick.When this occurs, the warning will first
come on intermittently and then stay on if
the oil level drops further.
If no oil leaks are noted, continue to drive
to the nearest service station where the
engine oil should be topped to the “full”
mark on the dipstick with an approved oil.
Display
Possible cause
Suggested solution
:
ENGINE OIL LEVEL
VISIT WORKSHOP!
The measuring system is malfunctioning.

Have the measuring system checked
by an authorized Mercedes-Benz
Center.
ENGINE OIL LEVEL
CHECK LEVEL!
The engine oil level is too low.

Check the engine oil level
(page 264) and add oil as required.
!The engine oil level warnings should
not be ignored. Extended driving with
the symbol displayed could result in se-
rious engine damage that is not cov-
ered by the Mercedes-Benz Limited
Warranty.