2005 BMW 645CI CONVERTIBLE ESP

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Fuel specifications
The engine uses unleaded gasoline only.
Required fuel
Premium unleaded gasoline
The minimum octane rating is 91.
If you use gasoline with this minimum octane
rating, the engine may produce knocking
sounds when starting at high outside tempera-
tures. This has no effect on the engine life.
Minimum Octane Rating corresponds to the
Anti Knock Index AKI and is determined accord-
ing to the so-called (R+M)/2 method.
Do not use leaded gasoline, as otherwise
the lambda probe and catalytic converter
will be permanently damaged.<
Use high-quality brands
Field experience has indicated significant dif-
ferences in fuel quality: volatility, composition,
additives, etc., among gasolines offered for sale
in the United States and Canada. Fuels contain-
ing up to and including 10 % ethanol or other
oxygenates with up to 2.8 % oxygen by weight,
that is, 15 % MTBE or 3 % methanol plus an
equivalent amount of co-solvent, will not void
the applicable warranties with respect to
defects in materials or workmanship.
The use of poor-quality fuels may result in
drivability, starting and stalling problems,
especially under certain environmental condi-
tions such as high ambient temperature and
high altitude.
Should you encounter drivability problems
which you suspect could be related to the fuel
you are using, we recommend that you respond
by switching to a recognized high-quality
brand.
Failure to comply with these recommendations
may also result in unscheduled maintenance.<

Wheels and tires
168
Wheels and tires
Tire inflation pressure
Information for your safety
It is not merely the tire's service life, but also
driving comfort and – to a great extent – driving
safety that depend on the condition of the tires
and the maintenance of the specified tire pres-
sure.
Checking tire inflation pressure
Only check tire inflation pressure when the tires
are cold. This means after a maximum of
1.25 miles/2 km driving or when the vehicle has
been parked for at least 2 hours. When tires are
warm, the tire inflation pressure increases.
Check the tire inflation pressure regularly
and correct it if necessary: at least every
two weeks and before beginning a longer trip. If
you fail to observe this precaution, you may be
driving on tires with incorrect tire pressures, a
condition that can not only compromise your
vehicle's stability, but also lead to tire damage
and the risk of an accident.<
After correcting the inflation pressure(s),
always reinitialize the Flat Tire Monitor,
refer to page84.<
Pressure specifications for factory-
installed tires
The tire inflation pressures with the ambient
temperature are visible on the door pillar with
the driver's door open.
Pressure specifications for other tire
sizes
The tables below provide all the correct inflation
pressures for the specified tire sizes at ambient
temperature.
For correct identification of the right tire
inflation pressure for your tires, observe
the specifications for the corresponding tire
size.<
Tire size
The specified pressures apply to tire sizes
approved by BMW and recommended tire
m a k e s ; y o u r B M W c en t e r w i ll b e g l a d t o p ro v id e
information.

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heat when tested under controlled conditions
on a specified indoor laboratory test wheel.
Sustained high temperature can cause the
material of the tire to degenerate and reduce
tire life, and excessive temperature can lead to
sudden tire failure. The grade C corresponds to
a level of performance which all passenger car
tires must meet under the Federal Motor Vehi-
cle Safety Standard No. 109. Grades B and A
represent higher levels of performance on the
laboratory test wheel than the minimum
required by law.
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive speed,
underinflation, or excessive loading, either sep-
arately or in combination, can cause heat
buildup and possible tire failure.<
RSC – run-flat tires
You will recognize run-flat tires by a circular
symbol containing the letters RSC on the side
of the tire, refer to page172.
M+S
Winter and all-season tires.
These have better winter properties than sum-
mer tires.
Tire condition
Inspect your tires frequently for tread wear,
signs of damage and foreign objects lodged in
the tread, and check the tread depth.
Minimum tread depth
The tread depth should not drop below 0.12 in/
3 mm, although, for example, European legisla-
tion only specifies a minimum tread depth of
0.063 in/1.6 mm.
At tread depths below 0.12 in/3 mm there is an
increased risk of high-speed hydroplaning,
even when only small amounts of water are
present on the road surface.
Winter tires noticeably loose their suitability for
winter use below a tread depth of 0.16 in/4 mm. New tires should be mounted in the interest of
safety.
Wear indicators at the tread-groove base, refer
to arrow, are distributed over the tire's circum-
ference and are marked on the side of the tire
with TWI – Tread Wear Indicator. If the indica-
tors are at the level of the profile, the legal per-
missible tread depth of 0.063 in/1.6 mm has
been reached.
Tire damage
Due to low-profile tires, please note that
wheels, tires and suspension parts are
more susceptible to road hazard and conse-
quential damages.
Unusual vibrations encountered during normal
vehicle operation can indicate tire failure or
some other vehicle defect. This can, for exam-
ple, be caused by driving over curbs. These
kinds of problems may also be signaled by other
changes in vehicle response, such as a strong
tendency to pull to the left or right.
In these cases reduce your speed immediately
and have the wheels and tires inspected imme-
diately. To do this, carefully drive to the next
BMW center or a specialized tire dealer which
works with personnel trained in accordance
with BMW specifications. Have the vehicle
towed to the workshop if necessary.
Tire damage can be extremely dangerous to
vehicle occupants and other road users.<
Unprofessional attempts by laymen to
service tires can lead to damage and acci-
dents. Have this work performed by skilled pro-
fessionals only. The technicians at your BMW
center will be glad to assist you with the
required professional knowledge and special-
ized equipment.<

Wheels and tires
172
Run-flat tires
You will recognize run-flat tires by the circular
symbol containing the letters RSC on the side-
wall.
Run-flat tires consist of self-contained tires and
special rims. The sidewall reinforcement
ensures that the tire retains some residual
safety in the event of pressure drop and driving
remains possible to a restricted degree.
New wheels and tires
Only have new wheels and tires mounted
by a BMW center or a specialized tire
dealer which works with personnel trained in
accordance with BMW specifications. If this
work is performed inexpertly, there is a danger
of damage and associated safety risks. Make
sure that the new wheels are balanced.<
Retreaded tires
BMW does not recommend the use of
retread tires, as otherwise driving safety
may be reduced. Possible variations in the
design and the age – which could be substan-
tial – of the carcasses can lead to more rapid
wear.<
The right wheels and tires
If you switch from summer to winter tires, or
vice versa, use run-flat tires, as in the event of a
flat tire there is no spare tire available. Your
BMW center will be glad to advise you.
For safety reasons, BMW recommends
that you do not have damaged run-flat
tires repaired; they should be replaced. wheel and tire combinations that BMW
has tested and approved for your particular
vehicle. Variations in factors such as manufac-
turing tolerances mean that even wheels and
tires with identical official size ratings could
actually have different dimensions than the
approved units – these differences could lead to
body contact, and with it the risk of severe acci-
dents. If non-approved wheels and tires are
used, BMW cannot evaluate their suitability,
and therefore cannot be held liable for driving
safety.<
You can find out the right wheel-tire combina-
tion from your BMW center.
The right wheel-and-tire combination is
another vital factor in ensuring reliable opera-
tion of various vehicle systems such as ABS
and DSC.
To maintain good handling and vehicle
response, use only tires of a single tread config-
uration from a single manufacturer. After a flat
tire, always remember to have the specified
wheel and tire combination remounted on the
vehicle as soon as possible.
Recommended tire brands
BMW tests certain tire brands for each tire size,
classifies them as road-safe and approves
them. Consult your BMW center for more infor-
mation. Observe any country-specific regula-
tions, e.g. on making a corresponding entry in
the vehicle documents.
The factory-mounted tires have been specially
selected to provide optimized performance
when installed on your vehicle; if properly cared
for, they will provide a combination of safety and
excellent ride comfort.
Special characteristics of winter tires
BMW recommends winter tires for use in cold
winter driving conditions. Although all-season
M+S tires provide better winter traction than
summer tires, they generally fail to provide the
same levels of cold-weather performance as
winter tires.

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Run-flat tires
If you switch from summer to winter tires, or
vice versa, use run-flat tires, refer to page172,
as in the event of a flat tire there is no spare tire
available. Your BMW center will be glad to
advise you.
Watch speed
Observe the permissible maximum speed
for the respective winter tires, as other-
wise tire damage and occur and cause acci-
dents.<
Storage
Always store wheels and tires in a cool, dry
place with as little exposure to light as possible.
Always protect tires against all contact with oil,
grease and fuels. Do not exceed the maximum
tire inflation pressure indicated on the side wall
of the tire.
Snow chains*
BMW only tests certain fine-link snow chains,
classifies them as road-safe and approves
them. Consult your BMW center for more infor-
mation. BMW recommends using these
approved snow chains. These snow chains are
approved exclusively for use in pairs on the rear
wheels with the tire size:
>245/50 R 17 Y
>245/45 R 18 Y
Observe the chain manufacturer's instructions
when mounting snow chains. Do not exceed a
vehicle speed of 30 mph/50 km/h with the
chains mounted.
Do not initialize the Flat Tire Monitor after
mounting snow chains.
When you are driving with snow chains, it can
be beneficial to switch off DTC briefly, refer to
page82.<

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2.Turn the cap of the expansion tank counter-
clockwise to allow any accumulated pres-
sure to escape, then continue turning to
open.
3.The coolant level is correct when it lies
between the Min and Max mark, also refer to
the drawing next the filler neck.
4.If the coolant is low, slowly add coolant up to
the specified level – do not overfill.
5.Turn the cap until it clicks.
6.Have the reason for the coolant loss elimi-
nated as soon as possible.
Brake system
Malfunction
Brake fluid
The warning lamp lights up in red
in spite of the handbrake being
released; a message appears on the
Control Display.
Stop the vehicle immediately.
The brake fluid in the reservoir has fallen to
below the minimum level. At the same time, a
significantly longer brake pedal path may be
noticeable. Have the system checked immedi-
ately by a BMW center.
Warning lamp for Canadian models.
When you continue driving, an increased
brake pedal path can be necessary, and
significantly longer braking distances might be
required. Please adapt your driving style
accordingly.<
Brake pads
The warning lamp lights up in red
in spite of the handbrake being
released; a message appears on the
Control Display. The brake pads have reached
their minimum pad thickness. Have the brake
pads replaced as soon as possible.Warning lamp for Canadian models.
For your own safety: use only brake pads
that BMW has approved for your particu-
lar vehicle model. As BMW cannot assess the
suitability of other brake pads for use on your
vehicle, BMW is unable to assume continued
responsibility for the vehicle's operating safety
if non-approved pads are installed.<

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OBD Socket
The Onboard Diagnostics OBD interface
socket is located on the left of the driver's side
under the instrument panel and under a cover.
The cover has the letters OBD on it.
The purpose of the OBD system is to ensure
proper operation of the emission control sys-
tem for the vehicle's lifetime. The system mon-
itors emission-related components and sys-
tems for deterioration and malfunction.
An illuminated indicator 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 cen-
ter at the earliest possible opportunity.
Display of the previously described
malfunction on Canadian models.
Under certain conditions, the indicator
lamp 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 seriously damage emissions control
components, especially the catalytic converter.
When the fuel filler cap is not properly
tightened, the OBD system can detect
the vapor leak and the indicator lamp will light
up. If the filler cap is subsequently tightened,
the indicator lamp should go out within a few
days.<
Event Data Recorders
Your vehicle may be equipped with one or more
sensing and diagnostic modules or a recording
device capable of recording or transmitting cer-
tain vehicle data or information. In addition, if
you have a Subscription Service Agreement for
the BMW Assist system, certain vehicle infor-
mation may be transmitted or recorded in order
to provide such services.
Care
Important information on care and maintenance
of your BMW is contained in the Caring for your
vehicle brochure.

Replacing components
180
Replacing components
Onboard tool kit
The onboard tool kit is located in the luggage
compartment under the floor mat.
Wiper blade replacement
1.Fold the wiper arm out and grasp it firmly.
2.Press the locking tabs together while slid-
ing the wiper blade toward the front to dis-
engage it.
Lamps and bulbs
Lamps and bulbs make an essential contribu-
tion to driving safety. Therefore, exercise suffi-
cient care when handling them. If you are not
familiar with the specified procedures, have the
corresponding work carried out at your BMW
center.Never touch the glass on new bulbs
with your bare fingers, as even minute
amounts of contamination will burn into the
bulb's surface and reduce its service life. Use a
clean cloth, napkin etc., or hold the bulb by its
metal socket.<
You can obtain a selection of replacement bulbs
at your BMW center.
When working on the lighting system
you should always switch off the lights
affected to prevent short circuits.
To avoid possible injury or equipment damage
when replacing bulbs, observe any instructions
provided by the bulb manufacturer.<
When performing maintenance on the head-
lamps, comply with the instructions in the sep-
arate Caring for your vehicle brochure.
In the case of bulbs where the replace-
ment is not described, please consult
your BMW center.<
Xenon lamps
The service life of these lamps is very long and
the probability of a failure is very low, provided
that they are not switched on and off an unusual
number of times. In the unlikely event that one
of these lamps should fail, you can continue
driving under poor visibility conditions by
switching on your fog lamps and proceeding
carefully, where allowed by law.
To avoid the risk of potentially fatal inju-
ries: owing to the extremely high voltages
at which these units operate, service work on
the xenon lighting system should only be car-
ried out by a BMW center.<