The ECO gauge shows the difference between the current rate of fuel consumption and the average rate of fuel consumption since the trip meter was last reset.
If the ECO gauge moves towards the + side, this indicates better fuel efficiency.
NOTE
This display shows the average vehicle speed since the trip meter was last reset. Pressing the TRIP RESET switch toggles the display between the average vehicle speed corresponding to the A trip meter display and the average vehicle speed corresponding to the B trip meter display. When either of the trip meter displays is reset, the corresponding average vehicle speed value is also reset.