This Ethanol Content Sensor measures the ratio of ethanol to petrol in a flex fuel vehicle. In order to adjust the ignition timing, fuelling and boost levels, the engine management system requires information about the percentage of ethanol in the fuel.
The pinout is indicated on the sensor itself (from left to right looking into connector on sensor) as :
1.) Vcc (+12V supply)
2.) GND (ground)
3.) Vout (digital signal out)