All cars
Hold [L1] + [L2] + [R1] + [R2] when the phrase "Push Start Button" appears at the title screen. A sound will confirm this portion of the code. Immediately hold [Up] + [Triangle], while keeping the previous buttons held. A sound will confirm this portion of the code. Press [Start], while keeping the previous buttons held.

Drive a sheep
Defeat all opponents in "School" mode. Then select "School" mode free trial. Hold [L2] + [R1] before entering the Zero 4 (1-1) course to use the Sheep.

All courses
Hold [L1] + [L2] + [R1] + [R2] when the phrase "Push Start Button" appears at the title screen. A sound will confirm this portion of the code. Immediately hold [Down] + [X], while keeping the previous buttons held. A sound will confirm this portion of the code. Press [Start], while keeping the previous buttons held. The course selection screen will appear.