Subaru Legacy Owner's Manual page 174

USEFUL INFORMATION
RESETTING THE LIFETIME FUEL CONSUMPTION
The lifetime fuel consumption can be reset.
1.
Display the "SETTINGS
2.
Select (Info).
Info
3.
Select (Eco Monitor).
Eco Monitor
4.
Select
Lifetime Fuel Cons Reset
Reset).
5.
Select (Yes).
Yes
172
(SETTINGS)" screen.
(Lifetime Fuel Cons