2003 Lexus IS300 wiring

GAUGES, METERS AND SERVICE REMINDER INDICATORS
47
(b) Driver's Seat Belt Reminder Light andBuzzer
This light and buzzer remind you to buckle up the driver's seat
belt.
Once the ignition key is turned to ºONº or ºSTARTº, the
reminder light flashes and buzzer sounds if the driver's seat
belt is not fastened. Unless the driver fastens the belt, the light
stays flashing and the buzzer stops after about 4 to 8 seconds.
(c) Front Passenger's Seat Belt Reminder Light
This light reminds you to buckle up the front passenger's seat
belt.
Once the ignition key is turned to ºONº or ºSTARTº, the
reminder light flashes if a passenger sits in the front passenger
seat and does not fasten the seat belt. Unless the front
passenger fastens the belt, the light stays flashing. However,
if a front passenger uses an additional seat cushion, the light
may not flash even when the seat belt is not buckled up.
If luggage load is placed on the front passenger seat,
depending on its weight and how it is placed on the seat,
built±in sensors in the seat cushion may detect the pressure,
causing the reminder light to come on.
(d) SRS Warning Light
The indicator comes on when the ignition key is turned to
the ºACCº or ºONº position. It goes off after about 6
seconds. This means the SRS airbags and front seat belt
pretensioners are operating properly.
The SRS warning light system monitors the airbag sensor
assembly, front airbag sensors, side and curtain shield airbag
sensors, front seat belt pretensioner assemblies, inflators,
warning light, interconnecting wiring and power sources.
If either of the following conditions occurs, this indicates a
malfunction somewhere in the parts monitored by the warning
light system. Contact your Lexus dealer as soon as possible
to service the vehicle.
 When the ignition key is turned to the ºACCº or ºONº
position, the light does not come on, remains on or flashes.
 The light comes on or starts flashing while driving.
If the light stays on, it indicates that the driver and front
passenger airbags fail. If the light flashes, the side and curtain
shield airbags and/or seat belt pretensioners fail.
2003 IS300 from Aug. '02 Prod. (OM53439U)

COMFORT ADJUSTMENT
123
SV16061
This indicator comes on when the ignition key is turned to
the ºACCº or ºONº position. It goes off after about 6
seconds. This means the front seat belt pretensioners are
operating properly.
The warning light system monitors the airbag sensor
assembly, front airbag sensors, side and curtain shield airbag
sensors, front seat belt pretensioner assemblies, inflators,
warning light, interconnecting wiring and power sources. (For
details, see ºService reminder indicators and warning buzzersº
on page 44.)
SV16068

1SRS warning light
2Front seat belt pretensioner assemblies
3Airbag sensor assembly
4Front airbag sensors
The front seat belt pretensioner system consists mainly of the
above components and their locations are shown in the
illustration.
The front seat belt pretensioners are controlled by the airbag
sensor assembly. The airbag sensor assembly consists of a
safing sensor and airbag sensor.
When the front seat belt pretensioners are activated, an
operating noise may be heard and a small amount of
smoke±like gas may be released. This gas is harmless and
does not indicate that a fire is occurring.
Once the front seat belt pretensioners have been activated, the
seat belt retractors remain locked.
2003 IS300 from Aug. '02 Prod. (OM53439U)

COMFORT ADJUSTMENT
124
CAUTION
Do not modify, remove, strike or open the front seat belt
pretensioner assemblies, airbag sensor or surrounding
area or wiring. Doing any of these may cause sudden
operation of the front seat belt pretensioners or disable
the system, which could result in death or serious
injury.
Failure to follow these instruction can result in death or
serious injury. Consult your Lexus dealer about any
repairs and modifications.
NOTICE
Do not perform any of the following changes without consulting your Lexus dealer. Such changes caninterfere with proper operation of the front seat beltpretensioners in some cases.
Installation of electronic devices such as a mobiletwo±way radio, cassette tape player or compact disc
player.
Repairs on or near the front seat belt retractor assemblies.
Modification of the suspension system.
Modification of the front end structure.
Attachment of a grille guard (bull bar, kangaroo bar,etc.), snowplow, winches or any other equipment tothe front end.
Repairs made on or near the front fenders, front endstructure or console.
2003 IS300 from Aug. '02 Prod. (OM53439U)

COMFORT ADJUSTMENT
128
CAUTION
The curtain shield airbags inflate with considerable
force. To avoid potential death or serious injury when
they inflate, the driver and front passenger must:
Wear their seat belts properly.
 Remain properly seated with their back upright and
against the seat at all times.
SV16061
The indicator comes on when the ignition key is turned to
the ºACCº or ºONº position. It goes off after about 6
seconds. This means the SRS airbags are operating
properly.
The SRS warning light system monitors the airbag sensor
assembly, front airbag sensors, side and curtain shield airbag
sensors, front seat belt pretensioner assemblies, inflators,
warning light, interconnecting wiring and power sources. (For
details, see ºService reminder indicators and warning buzzersº
on page 44.) The SRS front airbags are designed to deploy in severe
(usually frontal) collisions where the magnitude and
duration of the forward deceleration of the vehicle
exceeds the designed threshold level.
The SRS front airbags will work if the severity of the impact is
above the designed threshold level, comparable to an
approximate 25 km/h (15 mph) collision when the vehicle has
the impact straight into a fixed barrier that does not move or
deform.
However, this threshold velocity will be considerably higher if
the vehicle strikes an object, such as a parked vehicle or sign
pole, which can move or deform on impact, or if the vehicle is
involved in an underride collision (e.g. a collision in which the
nose of the vehicle ºunderridesº, or goes under, the bed of a
truck, etc.).
It is possible that in some collisions where the forward
deceleration of the vehicle is very close to the designed
threshold level, the SRS front airbags and the seat belt
pretensioners may not activate together.
For the safety of all occupants, always wear your seat belts
properly.
2003 IS300 from Aug. '02 Prod. (OM53439U)

COMFORT ADJUSTMENT
137
SV16150
Do not attach a microphone or any other device or
object around the part where the curtain shield airbag
activates such as on the windshield glass, side door
glass and front and side pillar. When the curtain
shield airbag inflates, the microphone or other device
or object will be thrown with great force or the curtain
shield airbag may not activate correctly, resulting in
death or serious injury.
 Do not use seat accessories which cover the parts
where the side airbags inflate. Such accessories may
prevent the side airbags from activating correctly,
causing death or serious injury.
 Do not modify or remove any wiring. Do not modify,
remove, strike or open any components, such as the
steering wheel pad, steering wheel, column cover,
front passenger airbag cover, front seats or airbag
sensor assembly. Doing so may cause sudden SRS
front airbags inflation or disable the system, which
could result in death or serious injury.
 Do not modify or replace the seats or upholstery of
front seats with side airbags. Such changes may
disable the system or cause the side airbags to inflate
accidentally, resulting in death or serious injury.
 Do not disassemble or repair the front pillar and roof
side containing the curtain shield airbags. Such
changes may disable the system or cause the curtain
shield airbags to inflate accidentally, resulting in
death or serious injury.
Failure to follow these instructions can result in death
or serious injury. Consult your Lexus dealer about any
repairs and modifications.
2003 IS300 from Aug. '02 Prod. (OM53439U)

STARTING AND DRIVING
229
HOW TO START THE ENGINE
Before cranking
1. Apply the parking brake firmly.
2. Turn off unnecessary lights and accessories.
3.Manual transmission : Press the clutch pedal to the floor
and shift the transmission into neutral. Hold the clutch pedal
to the floor until the engine is started. A starter safety device
will prevent the starter from operating if the clutch pedal is not
fully depressed.
Automatic transmission : Put the selector lever in ºPº. If you
need to restart the engine while the vehicle is moving, put the
selector lever in ºNº. A starter safety device will prevent the
starter from operating if the selector lever is in any drive
position.
4. For automatic transmission only :Depress the brake
pedal and hold it to the floor until driving off.
Starting the engine
Before starting the engine, be sure to follow the instructions in
ºBefore crankingº.
Normal starting procedure
The multiport fuel injection system/sequential multiport fuel
injection system in your engine automatically controls the
proper air±fuel mixture for starting. You can start a cold or hot
engine as follows:
1. With your foot off the accelerator pedal, crank the engine by
turning the key to ºSTARTº. Release it when the engine starts. 2. After the engine runs for about 10 seconds, you are ready
to drive.
If the weather is below freezing, let the engine warm up for a
few minutes before driving. Do not leave the vehicle while the
engine is warming up.
If the engine stalls ...
Simply restart it , using the correct procedure given in normal
starting.
If the engine will not start
See ºIf your vehicle will not startº on page 267.
NOTICE
Do not crank for more than 30 seconds at a time. This
may overheat the starter and wiring systems.
Do not race a cold engine.
If the engine becomes difficult to start or stallsfrequently, have the engine checked immediately.
2003 IS300 from Aug. '02 Prod. (OM53439U)

IN CASE OF AN EMERGENCY
268
(b) Starting a flooded engine
If the engine will not start, your engine may be flooded
because of repeated cranking.
If this happens, turn the key to ºSTARTº with the accelerator
pedal held down. Continue this operation for 30 seconds and
then stop cranking. Then try starting the engine with your foot
off the accelerator pedal.
If the engine does not start after 30 seconds of cranking,
release the key, wait a few minutes and try again.
If the engine still will not start, it needs adjustment or repair.
Call a Lexus dealer, Roadside Assistance or Customer
Service Assistance. (See ºForewordº.)
NOTICE
Do not crank for more than 30 seconds at a time. This
may overheat the starter and wiring systems.
(c) Jump starting
To avoid serious personal injury and damage to your
vehicle which might result from battery explosion, acid
burns, electrical burns, or damaged electronic
components, these instructions must be followed
precisely.
If you are unsure about how to follow this procedure, we
strongly recommend that you seek help from your Lexus
dealer, Roadside Assistance or Customer Service Assistance.
(See ºForewordº.)
CAUTION
 Batteries contain sulfuric acid which is poisonous
and corrosive. Wear protective safety glasses when
jump starting, and avoid spilling acid on your skin,
clothing, or vehicle.
 If you should accidentally get acid on yourself or in
your eyes, remove any contaminated clothing and
flush the affected area with water immediately. Then
get immediate medical attention. If possible,
continue to apply water with a sponge or cloth while
en route to the medical office.
 The gas normally produced by a battery will explode
if a flame or spark is brought near. Use only
standardized jumper cables and do not smoke or
light a match while jump starting.
2003 IS300 from Aug. '02 Prod. (OM53439U)

ELECTRICAL COMPONENTS
353
It is a good idea to purchase a set of spare fuses and keep them
in your vehicle for emergencies.
If the new fuse immediately blows out, there is a problem with
the electrical system. Have your Lexus dealer correct it as
soon as possible.
CAUTION
Never use a fuse with a higher amperage rating, or any
other object, in place of a fuse. This may cause
extensive damage and possibly a fire.
CHECKING THE CARTRIDGE TYPE
FUSES
SV64005

1Good 2Melted
If the headlights or other electrical components do not
work and the blade type fuses are O.K., check the
cartridge type fuses. If any of the cartridge type fuses are
blown, they must be replaced.
If there is an overload in the circuits from the battery, the fuses
are designed to blow before the entire wiring harness is
damaged.
2003 IS300 from Aug. '02 Prod. (OM53439U)