Security Indicator Light Circuit: Description
WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
When the theft deterrent system is in the disarmed state, the security indicator will flash continuously if the immobilizer system is set, or not illuminate if the immobilizer system is not set
When the theft deterrent system is in the armed state, the immobilizer system is automatically set and the security indicator will flash continuously.
When the theft deterrent system is in the arming preparation state and alarm sounding state, the certification ECU causes the security indicator to be illuminated