Fuel Injector Circuit [08/2015 - 08/2017]: Description
WARNING: This page is about a different car, the 2018 Toyota Sequoia, 2017 Toyota Sequoia, and 2016 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
The fuel injectors are located on the intake manifold. They inject fuel into the cylinders based on the signals from the ECM.