Technical Support

Ethanol content percent wrong or ethanol sensor not connected

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 in the 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 recognize ethanol sensor, eFlexFuel uses the ethanol content percent which was last read.

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

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

How to repair

  • Check that the ethanol sensor is not connected to the breather hose or any other than the fuel line
  • If the ethanol content varies, install the ethanol sensor to the pressure line
  • Broken fuel pump can also cause the variation of the ethanol content
  • Check that the ethanol sensor connector is properly connected
  • Check that the purple lock coupling is properly at the bottom. Push the coupling to the bottom if it is loose
  • Check terminals and pins that there are not oxygenated
  • Terminals should be straight in the connector. Check image below. If ethanol sensor has been attached in the wrong angle, the terminals may be flattened, disconnected and skewed so that the ethanol sensor will not connect properly or at all