The ethanol sensor continuously measures the ethanol content of the fuel. The ethanol content (if the fuel is changed) should increase or decrease after refueling. Depending on whether the ethanol sensor is installed in the return or pressure fuel line. The ethanol content should not change during driving if the vehicle is not refueled.


If ethanol sensor is not connected or control unit does not recognise ethanol sensor eFlexFuel uses last read ethanol content percent.

If ethanol sensor detects dirty fuel eFlexFuel uses 40 % ethanol contect percent.

Do not use vehicle if eFlexFuel App shows wrong ethanol content!

Fault diagnosis

  • Check that ethanol sensor is connected to fuel line.
  • If ethanol content varies install ethanol sensor to pressure line.
    • Faulty fuel pump can also affect to faulty ethanol content.
  • Check ethanol sensor connector is properly connected.
  • Check the purple lock coupling that it is properly at the bottom. Push the coupling to bottom if it is loose.
  • Check terminals and pins that there are not oxygenated.
  • Terminals should be straigt in the connector. Check image below. If ethanol sensor has been attached at the wrong angle, the terminals may be flattened, disconnected and skewed so that the ethanol sensor does not work properly.