Lexus 2004 GX470 Owner's Manual page 163

OCCUPANT RESTRAINT SYSTEMS
This indicator comes on when the ignition key is turned to
the "ON" 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, front airbag sensors, side and curtain shield airbag
sensor assemblies, curtain shield airbag sensor assemblies,
driver's seat position sensor, driver's seat belt buckle switch,
front seat belt pretensioner assemblies, inflators, warning light,
interconnecting wiring and power sources. (For details, see
"Service reminder indicators and warning buzzers" on page 55
for instructions.)
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If any of the following conditions occurs, this indicates a
malfunction of the airbags or seat belt pretensioners. Contact
your Lexus dealer as soon as possible.
D When the ignition switch is turned to the "ON" position, the
light does not come on, remains on or flashes.
D The light comes on or starts flashing while driving.
D If either front seat belt does not retract or cannot be pulled
out due to a malfunction or activation of the relevant front
seat belt pretensioner.