2000 Lexus LS400 sensor

SWITCHES
37
12L052
The automatic light control sensor is on top of the
driver's side instrument panel.
Do not place anything on the instrument panel, and/or do
not affix anything on the windshield to block this sensor.

GAUGES, METERS AND SERVICE REMINDER INDICATORS
66
(b) Driver's Seat Belt Reminder Lightand Buzzer
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.
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 indicators come 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 assemblies, inflators, seat belt pretensioners,
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 ªACCº or ªONº
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
airbags and/or seat belt pretensioners fail.

COMFORT ADJUSTMENT
155
Front seat belt pretensioners
16L239a
The driver and front passenger's seat belt
pretensioners are designed to be activated in
response to a severe frontal impact.
When the airbag sensor detects the shock of a severe
frontal impact, the front seat belt is quickly drawn back
by the retractor so that the belt snugly restrains the front
seat occupants.
The seat belt pretensioners are activated even with no
passenger in the front seat.
Collisions occurring at certain speeds and angles may
cause the seat belt pretensioners and SRS airbags not
to operate all together.

COMFORT ADJUSTMENT
156
16L136±2
This indicator comes on when the ignition key is
turned to the ªACCº or ªONº position. It goes off
after about 6 seconds. This means the front seat
belt pretensioners are operating properly.
This warning light system monitors the airbag sensor
assembly, inflator, seat belt pretensioner assembly,
warning light, interconnecting wiring and power sources.
(For details, see ªService reminder indicators and
warning buzzersº on page 62.)

COMFORT ADJUSTMENT
157
16L243b

1SRS warning light
2Seat belt pretensioner assembly
3Airbag sensor assembly
The seat belt pretensioner system consists mainly of the
above components, and their locations are shown in the
illustration.
The seat belt pretensioner is controlled by the airbag
sensor assembly. The airbag sensor assembly consists
of a safing sensor and airbag sensor.
When a seat belt pretensioner is 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 seat belt pretensioner has been activated, the
seat belt retractor remains locked.

COMFORT ADJUSTMENT
158
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 the instruction can result in death or
serious injury.

COMFORT ADJUSTMENT
165
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, side airbag sensor assemblies,
inflators, warning light, interconnecting wiring and power
sources. (For details, see ºService reminder indicators
and warning buzzersº on page 62.)
16L029

COMFORT ADJUSTMENT
166The SRS airbag system is designed to activate in
response to a severe frontal impact within the
shaded area between the arrows in the illustration.
The SRS airbags will work if the severity of the impact
is above the designed threshold level, comparable to an
approximate 20 km/h (14 mph) collision when impacting
straight
into a fixed barrier that does not move or deform.
If the severity of the impact is below the above threshold
level, the SRS airbags may not work. 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 it 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 at the lower zone of
airbag sensor detection and activation the SRS airbags
and seat belt pretensioners will not operate all together.
For the safety of all occupants, always wear your seat
belts.