2001 BMW 540I SEDAN check engine light

22n
Indicator and warning lampsTechnology that monitors itselfMany of the systems of your BMW
monitor themselves automatically, both
during engine starts and while you are
driving. Indicator and warning lamps
that are identified by "l" are tested for
proper functioning whenever the igni-
tion key is turned. They each light up
once for different periods of time.
If a fault should occur in one of these
systems, the corresponding lamp does
not go out after the engine is started or
it lights up while the vehicle is moving.
You will see how to react to this below.
Red: stop immediately
Battery charge current l
The battery is no longer being
charged. There is a malfunction
of the alternator V-belt or in the charg-
ing circuit of the alternator. Please con-
tact the nearest BMW center.
If the ribbed V-belt is defective, do
not continue driving. The engine
could be damaged due to overheating.
If the ribbed V-belt is defective, in-
creased steering effort is also re-
quired.<
Engine oil pressure l
Comes on while the engine is
running and the "STOP!ENGINE
OILPRESS" message appears in the
Check Control: stop vehicle immedi-
ately and switch off engine. Check level
of oil in engine, top up as required. If oil
level is correct: please contact the
nearest BMW center.
Do not continue driving. The en-
gine could be damaged because
of inadequate lubrication.<
Tire Pressure Control (RDC)
* l
In addition, there is an acousti-
cal warning signal: a tire failure
has occurred. Reduce vehicle speed
immediately and stop the vehicle. Avoid
hard brake applications. Do not over-
steer. For additional information: refer
to page 103.
Parking brake
*,
brake hydraulic system l
Comes on when you engage the
parking brake. For additional informa-
tion: refer to page 70.
Comes on although the parking brake is
released: have the brake fluid level
checked. Before driving further, be
sure to read the notes on pages 146
and 168.
Also comes on with the message
"CHECK BRAKE PADS" in the Check
Control.
Parking brake* warning lamp/
Brake hydraulic system for
Canadian models.

24n
Indicator and warning lamps
Automatic Stability Control plus
Traction (ASC+T)/Dynamic Sta-
bility Control (DSC)
* l
The ASC+T/DSC has been switched off
or has been deactivated because of a
malfunction. In the event of a malfunc-
tion, have the system checked by your
BMW center.
For additional information: refer to
page 102.
Engine electronics
*
There is a fault in the engine's
electronic control system. The
electronics allow for continued driving
with reduced engine output or rpms.
Please have the system inspected by
your BMW center.
Service Engine Soon l
If the indicator lamp comes on
either continuously or intermit-
tently, this indicates a fault in the emis-
sions-related electronic systems.
Although the vehicle remains opera-
tional, you should have the systems
checked by your BMW center at the
earliest possible opportunity.
For additional information: refer to
page 178.
Service Engine Soon warning
lamp for Canadian models.
Green: for your information
Turn signal
Flashes when the turn signals
are in operation. Rapid flashing
indicates a system malfunction.
For additional information: refer to
page 78.
Cruise control
Lights up when the cruise con-
trol is activated. Available for
operation via the multifunction steering
wheel.
For additional information: refer to
page 81.
Fog lamps
Lights up whenever you switch
on the fog lamps.
For additional information: refer to
page 106.
Blue: for your information
High beams
Lights up when the high beams
are on or the headlamp flasher
is actuated.
For additional information: refer to
pages 78 and 106.

IndexDataTechnologyRepairsCar careControlsOverview
85n
Coolant temperature gauge Service Interval DisplayBlueThe engine is still cold. Drive at moder-
ate engine and vehicle speeds.RedWhen you switch on the ignition, the
warning lamp
* comes on briefly to con-
firm that the system is operational.
If the the warning lamp lights up while
driving, or the message "Coolant tem-
perature" shows up in the Check Con-
trol
*, then the engine has overheated.
Switch the engine off immediately and
allow it to cool down.390de007
Between the blue and red zonesNormal operating range. It is not un-
usual for the needle to rise as far as the
edge of the red zone in response to
high outside temperatures or severe
operating conditions.
Checking coolant level: refer to
page 167.
The precise layout varies according to
the individual model version.
Green lampsThe number of illuminated lamps de-
creases as the time for your next main-
tenance visit approaches.Yellow lampThis field appears together with
OILSERVICE or INSPECTION.
Maintenance is due. Please contact
your BMW center for an appointment.Red lampThe maintenance deadline has been
passed.390us702

IndexDataTechnologyRepairsCar careControlsOverview
87n
Check Control>RELEASE PARKINGBRAKE
>COOLANT TEMPERATURE
The coolant is overheated. Stop the
vehicle immediately and switch off
the engine. Refer to pages 85
and 16 7.
>STOP!ENGINE OILPRESS
The oil pressure is too low. Stop the
vehicle immediately and switch off
the engine. Refer to page 22.
>CHECK BRAKE FLUID
Indicates that brake fluid is down to
roughly minimum level. Top up the
brake fluid at the next opportunity.
Refer to page 168. Have the source
of the brake fluid loss diagnosed and
corrected by your BMW center.
>TIRE DEFECT
*
Reduce vehicle speed immediately
and stop the vehicle. Avoid hard
brake applications. Do not oversteer.
Refer to page 104.
>SELFLEVEL SUSP.INACT
Please consult the nearest authorized
BMW center. Refer to page 148.
>SPEED LIMIT
*
Display if the programmed speed
limit has been exceeded.Priority 2
These displays appear for 20 seconds
when the ignition key is turned to posi-
tion 2. The warning symbols remain
after the message disappears. You can
display the messages again by pressing
the CHECK button 3:
>TRUNKLID OPEN
Message appears only when the
vehicle is initially set in motion.
>DOOR OPEN
This message appears after a mini-
mal defined road speed has been ex-
ceeded.
>FASTEN SEAT BELTS
*
In addition to this message, a
warning lamp with the safety belt icon
appears and an acoustical signal
sounds.
>WASHER FLUID LOW
Too low; top up fluid at the next
opportunity. Refer to page 164.
>CHECK ENGINE OIL LEV
The oil level is at the absolute mini-
mum, and therefore engine oil should
be added as soon as possible. Refer
to page 165. Until then, do not drive
more than approx. 30 miles (50 km)>CHECK FILLER CAP
Check that the filler cap is closed
correctly, refer to page 28. A loose or
missing cap will activate the message
"CHECK FILLER CAP" in the Check
Control
* or the Service Engine Soon
lamp.
>OUTSIDE TEMP. +207 (–56)
This display is only an example. The
current temperature is displayed at
outside temperatures of +37.57
(+36) and below. Refer also to
page 83.
>SET TIRE PRESSURE
*
The RDC has imported the current in-
flation pressure in the tires as the tar-
get values which the system will
monitor. Refer to page 103.
>CHECK TIRE PRESSURE
*
Check and correct the tire inflation
pressure to specifications at the earli-
est opportunity (next stop for fuel).
Refer to page 104.
>TIRECONTROL INACTIVE
*
A temporary interference of the RDC
or a system fault. Refer to page 104.
>CHECK BRAKE LIGHTS
A lamp has failed or the electrical cir-
cuit has a fault. Refer to pages 186
and 196 or consult a BMW center.

88n
Check Control>CHECK LOWBEAM LIGHTS
CHECK SIDE LIGHTS
CHECK REAR LIGHTS
CHECK FRONT FOGLAMPS
CHECK LICPLATE LIGHT
CHECK HIGHBEAM LIGHTS
CHECK BACK UP LIGHTS
Defective bulb or circuit. Refer to
pages 183 and 196 or consult your
BMW center.
>TRANS. FAILSAFE PROG
Please consult the nearest BMW
center. Refer to pages 74, 77.
>CHECK BRAKE LININGS
Have the brake pads inspected by
your BMW center. Refer to page 146.
>CHECK COOLANT LEVEL
Coolant too low, top up at the next
opportunity. Refer to page 167.
>ENGINE FAILSAFE PROG
*
The electronics allow for continued
driving with reduced engine output or
rpms.
Please have the system inspected by
your BMW center.
Displays after completion of tripAll of the malfunctions registered during
the trip appear consecutively when the
key is turned to position 0.
One of the following displays may ap-
pear:
>LIGHTS ON
>KEY IN IGNITION LOCK
>CHECK ENGINE OIL LEV
Add engine oil at the next opportunity
(next stop for fuel). Refer to page 16 5.
Display appears when you open the
driver's door after parking the vehicle.
A supplementary gong is also heard.
Status reports remain available for a
period of approx. three minutes after
the display goes out and the key is re-
moved from the ignition. Press the
CHECK button. If there were multiple
reports, press the CHECK button re-
peatedly to view them all in sequence.
To check the Check ControlPress the CHECK button 3 with the
ignition key in position 2:
CHECK CONTROL OK appears in the
display.
No malfunctions are present in the
monitored systems.
You can have the Check Control
messages displayed in a different
language.<

IndexDataTechnologyRepairsCar careControlsOverview
105n
Parking lamps
(side marker lamps)
With the switch in this position,
vehicle lighting is illuminated on
both sides. For lighting on one
side for parking as an additional fea-
ture, refer to page 106.
Low beams/Xenon lamps
*
When the ignition is switched off
and the low beams are on, only
the parking lamps (side marker
lamps) remain on.
390de034
"Follow-me-home lighting:"
If you actuate the headlamp
flasher after you have parked the
vehicle and shut off the engine, the low
beams will remain on for a brief period.
You may also have this function deacti-
vated if you wish.<
Xenon lamps
*
For additional details, refer to
page 184."LIGHTS ON" warning In ignition key position 0, a buzzer
sounds for a few seconds after the
driver's door is opened if the head-
lamps have not been switched off
.
On vehicles with alphanumeric
Check Control
*:
The reminder is given through the
Check Control.
Daytime-driving lamp
*
The headlamps are automatically
switched on for daylight driving at
ignition key position 2.
Turn the rotary dial to adjust the illumi-
nation intensity.390de036
Parking lamps/Low beamsInstrument lighting

Index
Data
Technology
Repairs
Car care
Controls
Overview
145nDisc brakes
Driving notes
When driving in wet conditions and in
heavy rain, it is effective to apply light
pressure to the brake pedal every few
miles (kilometers). Watch traffic condi-
tions to ensure that this maneuver does
not endanger other road users. The
heat which is generated by the brake
applications helps to dry the brake
pads and rotors.
Maximum braking force is obtained
while the wheels continue to rotate,
peaking when the wheels remain on the
verge of locking without actually doing
so. ABS maintains this state automati-
cally. If the ABS fails, you should revert
to the staggered braking technique
described below (refer to page 147).
Extended or steep mountain descents
should be driven in the gear in which
only minimal periodic brake applica-
tions is required. This avoids excessive
strain on the brakes and possible im-
pairment of the braking effect.
The braking effect of the engine can be
further increased by downshifting, into
first gear, if necessary. In the manual
mode of the automatic transmission,
you can also downshift into first gear.
Refer to page 76. Should engine braking prove inade-
quate, you should still avoid extended,
continuous braking. Instead of main-
taining low to moderate pressure over
an extended period of time, you should
decelerate by applying more substantial
pressure to the brake pedal (watch for
following traffic!), then releasing the
pedal, then repeating the application.
This staggered braking technique
allows the brakes to cool in the intervals
between active braking phases,
preventing overheating and ensuring
that full braking capacity remains avail-
able at all times.
Do not coast with the clutch de-
pressed or with the transmission
or selector lever in Neutral. Do not
coast with the engine shut off. The
engine provides no braking effect when
the clutch is depressed or the transmis-
sion is in neutral, and there is no
power-assist for braking or steering
when the engine is not running.
Never allow floor mats, carpets or any
other objects to protrude into the area
around the accelerator, clutch and
brake pedals and obstruct their move-
ment. <
Dynamic Brake Control (DBC)*
If you apply the brakes rapidly, this
system automatically produces the
maximum braking force boost and thus
helps to achieve the shortest possible
braking distance during "panic stops."
All of the benefits of the ABS system
are exploited under these circum-
stances.
Do not reduce the pressure on the
brake pedal for the duration of the
brake application. When the brake
pedal is released, the DBC is deacti-
vated.
In the event of a malfunction, the yellow
warning lamp comes on. Conventional
braking efficiency is available without
limitations.
Have the system checked and repaired
at your BMW center as soon as possi-
ble.
For "Information for your safety"
covering the ABS system, refer to
page 144. This information also gener-
ally applies for DBC. <

178nOBD interface socket
The Onboard Diagnostic (OBD) socket
is located on the left of the driver's side
at the bottom of the instrument panel
and under a cover (arrow).
The cover has the letters "OBD" on it.
The purpose of the OBD system is to
ensure proper emission control system
operation for the vehicle's lifetime by
monitoring emission-related compo-
nents and systems for deterioration and
malfunction.
390us249
An illuminated lamp informs you
of the need for service, not of
the need to stop the vehicle.
However, the systems should be
checked by your BMW center at the
earliest possible opportunity.
Under certain conditions, the indicator
will blink or flash. This indicates a rather
severe level of engine misfire. When
this occurs, you should reduce speed
and consult the nearest BMW center as
soon as possible. Severe engine misfire
over only a short period of time can se-
riously damage emission control com-
ponents, especially the catalytic con-
verter.
Service Engine Soon warning
lamp for Canadian models.When the filler cap is not properly
tightened, the OBD system can
detect the vapor leak and the indicator
will light up. If the filler cap is subse-
quently tightened, the indicator should
extinguish within a few days. <