Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Reconnect negative battery cable. Perform SYSTEM OPERATION CHECK . If AIR BAG warning light does not illuminate, replace air bag sensor assembly. If AIR BAG warning light is still illuminated, repair AIR BAG warning light circuit Black/Yellow wire or circuit AB (Black/Yellow wire) leading to the DLC3. See WIRING DIAGRAMS .