If your vehicle is AWD (All-Wheel Drive) with an automatic transmission and the temporary spare tire has been installed, put a spare fuse (15 amp) inside the FWD (Front-Wheel Drive) fuse holder (refer to your owner's manual for location). Confirm that the Front-Wheel Drive (FWD) warning light comes on before you drive the car. Installation of this fuse deactivates AWD to prevent possible damage to the drivetrain components that can result due to the use of the smaller temporary spare tire. After re-installing the conventional tire, remove the fuse from the FWD fuse holder to restore AWD operation.
For more information on tires and temporary spare tire usage, always consult your Subaru owner's manual.