Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Fuel Composition Sensor (FCS), or Flex Fuel Sensor The fuel composition sensor (FCS), or flex fuel sensor (service parts term), measures the ethanol-gasoline ratio of the fuel being used in a flexible fuel vehicle. Flexible fuel vehicles can be operated with a blend of ethanol and gasoline, up to 85 percent ethanol. In order to adjust the ignition timing and the fuel quantity to be injected, the engine management system requires information about the percentage of ethanol in the fuel.
If required, install the fuel composition sensor to the bracket and install the bolts