Looking to run flex-fuel? Then the Ethanol Content Sensor is a must have. The Ethanol Content Sensor measures the ratio of ethanol to petrol in a flex fuel vehicle. This sensor also measures fuel temperature. Compatible with all current Link Wire-In and Plug-In ECU’s. Uses 1 Digital input on the ECU. The sensor is fitted to the vehicle’s fuel return line anywhere between the fuel pressure regulator and the fuel tank.