Cold Start Injector Circuit: Description
WARNING: This page is about a different car, the 2009 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
The cold start injector is attached to the intake air surge tank and is designed to improve startability when the engine is cold. It operates when the engine coolant temperature is -12°C or less, and the starter signal is ON.