Cold Start Injector Circuit [04/2013 - 08/2015]: Description
WARNING: This page is about a different car, the 2015 Lexus IS 250 and 2014 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
The cold start fuel injector assembly 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 (10°F) or less, and the starter signal is on.