Distance Control ECU Power Source Circuit: Description
WARNING: This page is about a different car, the 2008 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
This circuit provides power to operate the distance control ECU. The distance control ECU determines the vehicle that you are following based on data from the laser sensor and then decides how much acceleration and/or deceleration is needed to maintain the set distance. It also requests the skid control ECU to apply braking and sound the buzzer.