check engine MERCEDES-BENZ SL-Class 2001 R129 Owner's Guide

202 Check regularly and before a long trip
Te ch n ica l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Check regularly and before a long trip 1Coolant level
See “Adding coolant” on page 224.
2Windshield washer and
headlamp cleaning system
For refilling reservoir see page 226.
3Engine oil level
See “Checking engine oil level” on page 222 and
“Engine oil level indicator” on page 82.
4Brake fluid
See “Brake fluid” on page 279.
Opening hood, see page 220.
Ve h i c l e l i g h t i n g : Check function and cleanliness. For
replacement of light bulbs, see “Exterior lamps” on page
243.
Exterior lamp switch, see page 84.

203 Contents - Instrument cluster display
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
Instrument cluster display Malfunction and indicator
lamps in the
instrument cluster ....................204
On-board
diagnostic system .......................204
Check engine malfunction
indicator lamp .............................204
Brake warning lamp ..................205
Brake pad wear
indicator lamp .............................205
Seat belt warning lamp .............206
Supplemental
restra int system
(SRS) indicator lamp ..................206Fuel reserve and fuel cap
placement warning ................... 207
Electronic stability program
(ESP)- warning lamp ................. 207
BAS/ESP malfunction
indicator lamp ............................ 207
ABS malfunction
indicator lamp ............................ 208
Low engine coolant
level warning lamp .................... 209
Low windshield and
headlamp washer
system fluid level
warning lamp ..............................210
Low engine oil level
warning lamp ..............................210Charge indicator lamp ............... 211
Exterior lamp failure
indicator lamp ............................. 211
Roll bar warning lamp ............... 212
ADS indicator lamp .................... 212
High beam
indicator lamp ............................. 213
Additional function
indicator lamps
(in the odometer display) .......... 213
Malfunction and
indicator lamp
(in the dashboard) .................... 213
Passenger airbag
indicator lamp ............................. 213

204 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
Malfunction and indicator lamps
in the instrument cluster
General information:
If a bulb in the instrument cluster fails to light up
during the bulb self-check when turning the electronic
key in steering lock to position 2, have it checked and
replaced if necessary.
On-board diagnostic system
Check engine malfunction indicator lamp
Engine malfunction indicator lamp. If the
“CHECK ENGINE” malfunction indicator
lamp comes on when the engine is running,
it indicates a malfunction of the fuel management
system, emission control system, systems which impact
emissions, or the fuel cap is not closed tight (check the
fuel cap). If the “CHECK ENGINE” lamp is illuminated
continuously and the vehicle is driving normally, you
may still drive the vehicle, however, in all cases, we
recommend that you have the system checked at your
authorized Mercedes-Benz Center as soon as possible. If the “CHECK ENGINE” lamp comes on continuously
and / or the vehicle is not driving normally, serious
damage can occur to the emission system. Please
contact your authorized Mercedes-Benz Center
immediately.
The Sequential Multiport Fuel Injection (SFI) control
module monitors emission control components that
either provide input signals to or receive output signals
from the control module. Malfunctions resulting from
interruptions or failure of any of these components are
indicated by the “CHECK ENGINE” malfunction
indicator lamp in the instrument cluster and are
simultaneously stored in the SFI control module.
If the “CHECK ENGINE” malfunction indicator lamp
comes on, have the system checked at your authorized
Mercedes-Benz Center as soon as possible.
With some exceptions, the control module switches off
the “CHECK ENGINE” malfunction indicator lamp if the
condition, causing the lamp to come on, no longer exists
during three consecutive cycles. See also page 207 for
fuel cap placement warning.

205 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index An on-board diagnostic connector is located in the
passenger compartment near the engine hood release,
allowing the accurate identification of system
malfunctions through the readout of diagnostic trouble
codes.
Brake warning lamp
Except Canada
Canada only
With the key in steering lock position 2, the brake
warning lamp will come on. It should go out when the
engine is running.
The brake warning lamp will come on:
• when there is insufficient brake fluid in the
reservoir (engine running and parking brake
released), or
• when the parking brake is set (engine running).Note:
If you find that the minimum mark on the brake fluid
reservoir is reached, have the brake system checked for
brake pad thickness and leaks.
Brake pad wear indicator lamp
With the key in steering lock position 2, the
brake pad wear indicator lamp comes on. It
goes out when the engine is running.
If the indicator lamp lights up during braking, this
indicates that the brake pads are worn down.
Have the brake system checked at your authorized
Mercedes-Benz Center as soon as possible.
Wa r n i n g !
Driving with the brake warning lamp illuminated
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.

206 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
Seat belt warning lamp
With the key in steering lock position 2, the
seat belt warning lamp comes on, and a
warning sounds for a short time if the
drivers seat belt is not fastened.
If a backrest is not engaged in its lock, a warning will
sound intermittently for up to approx. 20 seconds.
After starting the engine, the seat belt warning lamp
blinks for a brief period to remind the driver and
passengers to fasten seat belts before driving off.
If the warning lamp does not go out after blinking
briefly, but is instead lit continuously, then a backrest is
not engaged in its lock.
The warning lamp goes out as soon as the backrest is
engaged in its lock.
If the backrest is locked and the warning lamp does not
go out, have the system checked at your authorized
Mercedes-Benz Center as soon as possible.Supplemental restraint system (SRS) indicator lamp
The operational readiness of the airbag
system is verified by the indicator lamp
“SRS” in the instrument cluster when
turning the key in steering lock to position 1 or 2. If no
fault is detected, the lamp will go out after
approximately 4 seconds; after the lamp goes out, the
system continues to monitor the components and
circuitry of the airbag system and will indicate a
malfunction by coming on again.
See page 60 for notes on airbags, see page 59 for belt
tensioners and page 68 for infant and child seat
restraint.
Wa r n i n 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 authorized
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 also
result in injury.

207 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index Fuel reserve and fuel cap placement warning
With the key in steering lock position 2, the
fuel reserve warning lamp comes on. It
should go out immediately when the engine
is running.
If the warning lamp does not go out after starting the
engine, or if it comes on while driving, it indicates that
the fuel level is down to the reserve quantity of
approximately 2.6 gal (10 liters).
The warning lamp blinks when the fuel cap is not
closed, or a fuel system leak has been detected.
Retighten cap and see if warning lamp goes out after
restart and next OBD selfcheck.
If the warning lamp continues to blink after closing the
fuel cap correctly, have the fuel system checked at your
authorized Mercedes-Benz Center as soon as possible.
Leaving the engine running and the fuel cap open can
cause the “CHECK ENGINE” lamp to illuminate (see also
page 204).Electronic stability program (ESP) — warning lamp
The yellow ESP warning lamp in the
speedometer dial comes on with the key in
steering lock position 2. It should go out
with engine running.
See page 192 if the warning lamp lights up or flashes
when the vehicle is moving.
BAS/ESP malfunction indicator lamp
The malfunction indicator lamp for the ESP
is combined with that of the BAS.
The yellow BAS/ESP malfunction indicator
lamp in the instrument cluster comes on with the key in
steering lock position 2. It should go out with the engine
running.
If the BAS/ESP malfunction indicator lamp comes on
permanently with the engine running, see page 188
and 192.

208 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
ABS malfunction indicator lamp
The ABS malfunction indicator lamp in the
instrument cluster comes on with the key in
steering lock position 2 and should go out
with the engine running.
When the ABS malfunction indicator lamp symbol and
warning in the instrument cluster come on while the
engine is running, it indicates that the ABS has detected
a malfunction and has switched off. In this case, the
brake system functions in the usual manner, but
without antilock assistance.
With the ABS malfunctioning, the BAS and ESP are also
switched off. Both malfunction indicator lamps come on
with the engine running.If the charging voltage falls below 10 volts, the
malfunction indicator lamp comes on and the ABS is
switched off. When the voltage is above this value again,
the malfunction indicator lamp should go out and the
ABS is operational.
Have the system checked at your authorized
Mercedes-Benz Center as soon as possible.
See page 190 for notes on antilock brake system (ABS).
ABS

209 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index Low engine coolant level warning lamp
With the key in steering lock position 2, the
warning lamp comes on. It should go out
when the engine is running.
If the warning lamp does not go out after starting the
engine, or if it comes on while driving, then the coolant
level has dropped below the required level. If no leaks
are noticeable and the engine temperature does not
increase, continue to drive to the nearest service station
and have coolant added to the coolant system,
see page 225.
The low engine coolant level warning light should not be
ignored. Extended driving with the light illuminated
may cause serious engine damage not covered by the
Mercedes-Benz Limited Warranty.In cases of major or frequent minor coolant loss, have
the cooling system checked at your authorized
Mercedes-Benz Center as soon as possible.
Note:
Do not drive without coolant in the cooling system. The
engine will overheat causing major engine damage.
Monitor the coolant temperature gauge while driving.
Wa r n i n 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.

210 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
Low windshield and headlamp washer system fluid
level warning lamp
With the key in steering lock position 2, the
warning lamp comes on. It should go out
when the engine is running.
If the warning lamp does not go out after starting the
engine, or if it comes on while driving, the level of the
reservoir has dropped to approx. 1/3 of the total volume.
The reservoir should be refilled with MB Windshield
Washer Concentrate “S” and water (or commercially
available premixed windshield washer solvent/
antifreeze, depending on ambient temperature - see
page 88) at the next opportunity. The reservoir for the
windshield and headlamp washer systems is located in
the engine compartment.Low engine oil level warning lamp
With the key in steering lock position 2, the
oil level warning lamp comes on. It should
go out immediately when the engine is
running.
If the warning lamp does not go out after starting the
engine, or comes on with the engine running and at
operating temperature, the engine oil level has dropped
to approximately the minimum mark on the dipstick.
When this occurs, the warning lamp will first come on
intermittently and then stay on if the oil level drops
further.
If no 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.
The low engine oil level warning light should not be
ignored. Extended driving with the light illuminated
could result in serious engine damage that is not
covered by the Mercedes-Benz Limited Warranty.
In addition to the warning lamp, the engine oil level
should be periodically checked with the dipstick, for
example during a fuel stop, or before a long trip,
see page 222.

212 Malfunction and warning messages
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
Roll bar warning lamp
With the key in steering lock position 2, the
roll bar warning lamp comes on and goes out
with the engine running.
Have the roll bar system checked at your authorized
Mercedes-Benz Center as soon as possible.ADS indicator lamp
If the malfunction indicator stays on after
the engine is running, then the oil level in
the reservoir is low or the system has
detected a malfunction.
Have the ADS checked at your authorized
Mercedes-Benz Center as soon as possible.
For detailed information see page 199
Wa r n i n g !
If the warning lamp does not go out after starting
the engine, or if it comes on while driving, and the
indicator lamps in the roll bar switch blink
simultaneously, then the roll bar system is not
operating properly and may not activate in an
accident. In this case, raise the roll bar manually
(see page 118) before continuing to drive.