An ACDelco GM Original Equipment Flex Fuel Sensor monitors the ethanol content of the fuel in your flex fuel vehicle, and is a GM-recommended replacement for your vehicle's original component. The flex fuel sensor signal is used by the engine control module to adjust the air/fuel mixture and ignition timing for efficient operation. This original equipment flex fuel sensor has been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.