warning light LEXUS GS400 2000 Service Owner's Guide

RS01Y±06
± SUPPLEMENTAL RESTRAINT SYSTEMSRS AIRBAG
RS±1
2232 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
SRS AIRBAG
PRECAUTION
NOTICE:

The LEXUS GS 400/300 is equipped with SRS, which comprises a driver airbag, front passenger
airbag and side airbag. Failure to carry out service operations in the correct sequence could
cause the SRS to unexpectedly deploy during servicing, possibly leading to a serious accident.
Further, if a mistake is made in servicing the SRS, it is possible that the SRS may fail to operate
when required. Before performing servicing (including removal or installation of parts, inspec-
tion or replacement), be sure to read the following items carefully, then follow the correct proce-
dures described in the repair manual.

Malfunction symptoms of the SRS are difficult to confirm, so the DTCs become the most impor-
tant source of information when troubleshooting. When troubleshooting the SRS, always in-
spect the DTCs before disconnecting the battery.

Even in cases of a minor collision where the SRS does not deploy, the steering wheel pad, front
passenger airbag assembly, side airbag assembly, airbag sensor assembly, front airbag sen-
sor and side airbag sensor assembly should be inspected (See page RS±15, RS±29, RS±42
, RS±60 and RS±65).

Never use SRS parts from another vehicle. When replacing parts, replace them with new parts.

Never disassemble and repair the steering wheel pad, front passenger airbag assembly, side
airbag assembly, airbag sensor assembly, front airbag sensor or side airbag sensor assembly
in order to reuse it.

If the steering wheel pad, front passenger airbag assembly, side airbag assembly, airbag sen-
sor assembly, front airbag sensor or side airbag sensor assembly has been dropped, or if there
are cracks, dents or other defects in the case, bracket or connector, replace them with new
ones.

Use a volt/ohmmeter with high impedance (10 kW/V minimum) for troubleshooting the system's
electrical circuits.

Information labels are attached to the periphery of the SRS components. Follow the instruc-
tions on the notices.

After work on the SRS is completed, perform the SRS warning light check or SRS side airbag
warning light check (See page DI±552).

If the vehicle is equipped with a mobile communication system, refer to the precaution in the
IN section.
CAUTION:

Work must be started after 90 seconds from when the ignition switch is turned to the ºLOCKº
position and the negative (±) terminal cable is disconnected from the battery.
(The SRS is equipped with a back±up power source so that if work is started within 90 seconds
from disconnecting the negative (±) terminal cable of the battery, the SRS may be deployed.)

When the negative (±) terminal cable is disconnected from the battery, the memory of the clock
and audio system will be canceled. So before starting work, make a record of the contents mem-
orized in the audio memory system. When work is finished, reset the audio systems as they
were before and adjust the clock. To avoid erasing the memory in each memory system, never
use a back± up power supply from outside the vehicle.

Before repairs, remove the airbag sensor if shocks are likely to be applied to the sensor during
repairs.

Do not expose the steering wheel pad, front passenger airbag assembly, side airbag assembly,
airbag sensor assembly, front airbag sensor or side airbag sensor assembly directly to hot air
or flames.

H02575
H02574
H02700
H02576
± SUPPLEMENTAL RESTRAINT SYSTEMSRS AIRBAG
RS±3
2234 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. SRS WARNING LIGHT
The SRS warning light is located on the combination meter. It
goes on to alert the driver of trouble in the system when a mal-
function is detected in the airbag sensor assembly. In normal
operation conditions when the ignition switch is turned to the
ACC or ON position, the light goes on for apporx. 6 seconds and
then goes off.
7. AIRBAG SENSOR ASSEMBLY
The airbag sensor assembly is mounted on the floor inside the
lower center finish panel. The airbag sensor assembly consists
of an airbag sensor, safing sensor, diagnosis circuit, ignition
control and drive circuit, etc. It receives signals from the airbag
sensor and judges whether the SRS must be activated or not.
8. FRONT AIRBAG SENSOR
The front airbag sensor is mounted inside each of the front
members. The sensor unit is a mechanical type. When the sen-
sor detects deceleration force above a predetermined limit,
contact is made in the sensor, sending a signal to the airbag
sensor assembly. The sensor cannot be disassembled.
9. SIDE AIRBAG SENSOR ASSEMBLY
The side airbag sensor assembly is mounted in the LH and RH
center pillar. The side airbag sensor assembly consists of a side
airbag sensor, safing sensor, diagnosis circuit, ignition control
and drive circuit, etc. It receives signals from the side airbag
sensors and judges whether the SRS side airbag must be acti-
vated or not.

R12076Airbag Sensor AssemblyDisconnection
Detection
PinSRS
Warning
Light
H00955
Terminal for Diagnosis
Disconnection Detection Pin
Half Connection
Complete Connection
Terminal for
Diagnosis
RS±6
± SUPPLEMENTAL RESTRAINT SYSTEMSRS AIRBAG
2237 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HINT:
The type of connector shown on the previous page is used for
the spiral cable connector º5º on the airbag sensor assembly
side.
(3) Electrical Connection Check Mechanism
This mechanism electrically checks that connectors
are connected correctly and completely. The electri-
cal connection check mechanism is designed so
that the disconnection detection pin connects with
the diagnosis terminals when the connector hous-
ing lock is locked.
HINT:
The above illustration shows connectors º1º, º2º and º3º.

RS084±01
H02621
Combination Meter
(Warning Light)
Steering Wheel Pad
(with Airbag)
Spiral CableRH Front Airbag SensorFront Passenger Airbag Assembly
RH Side Airbag
Assembly
RH Side Airbag
Sensor Assembly
RH Seat Belt
Pretensioner
Airbag Sensor Assembly LH Side Airbag
Assembly LH Seat Belt
Pretensioner LH Side Airbag
Sensor Assembly LH Front Airbag
Sensor
RS±68
± SUPPLEMENTAL RESTRAINT SYSTEMWIRE HARNESS AND CONNECTOR
2299 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
WIRE HARNESS AND CONNECTOR
LOCATION