Circuit Description
WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
When the key is inserted in the ignition key cylinder, the key unlock warning switch comes ON and when the key is not inserted the switch is OFF. When the key unlock warning switch is ON, the instrument ECU (body ECU) operates the key confinement prevention function. See Fig 1.