The Racer X Fabrication flex fuel kit for the 2012+ Chevy Sonic allows for the use of E85 fuel. The flex fuel kit uses a latest generation flex fuel sensor that is lighter and has faster response times compared to previous models. We include a harness that needs to be wired into your existing OEM electrical system. In addition, a simple fuse block allows for the adaptation of a switched 12v+ power source that can be conveniently wired into the engine bay fuse box. The kit requires tuning to utilize E85 fuel.