This code indicates the engine control module has detected fuel ethanol content outside the expected operating range. It typically occurs in Flex Fuel vehicles equipped with a dedicated fuel composition sensor. The system triggers the light when the sensor signal does not match expected parameters for the current engine operation.
The sensor itself frequently fails due to prolonged exposure to fuel chemicals and ethanol corrosion.
The vehicle may have been filled with a fuel mixture that exceeds the designed ethanol tolerance limits.
Harness damage or corrosion at the sensor connector can interrupt or skew the signal sent to the computer.
Water or sediment in the fuel tank can interfere with the sensor's ability to accurately read fuel composition.
The control module software may require an update to correctly interpret sensor data under certain conditions.
Internal hardware failure within the engine computer is extremely rare and should only be considered after all other causes are ruled out.
Yes, fuel with an ethanol content higher than the vehicle is designed to handle can trigger this code.
Caution is advised as incorrect fuel mixture detection can lead to poor performance or engine stalling.
No, this code almost always indicates a sensor or fuel issue, and replacing the computer is rarely the correct fix.
If the cause is incorrect fuel type, draining and refilling may resolve it, but a failed sensor will still require replacement.