Go to the screen with "Start" and a picture of the car. Hold L + R, then press Up/Left + B. If you entered the code correctly, you will hear a chime.
All cars and modes
Enter "S/PD W1/H L8Q8 >VbB" as a case-sensitive password to unlock all cars and modes.
All tracks
Go to the screen with "Start" and a picture of the car. Hold L + R, then press Up/Right + B. If you entered the code correctly, you will hear a chime.
All tune-ups
Go to the screen with "Start" and a picture of the car. Hold L + R, then press Down/Right + B. If you entered the code correctly, you will hear a chime.
Extra mode 1
Go to the screen with "Start" and a picture of the car. Hold L + R, then press Right + B. If you entered the code correctly, you will hear a chime. Alternately, select championship mode and win the beginner, middle, and high speed classes. An "Extra 1" option will now be unlocked at the main menu. Select it to race in mini-cars.
Extra mode 2
Go to the screen with "Start" and a picture of the car. Hold L + R, then press Left + B. If you entered the code correctly, you will hear a chime. Alternately, select championship mode and win all four classes. You must finish in first place in all races. This will unlock the Formula 1 car and the "Extra 2" option at the main menu.
Formula 1 Mode
To access the Extra Formula 1 mode play through the championship mode and beat all four of the classes with a first place in each race. You will get a new car after the last race. It is a Formula 1 race car. At the menu screen the Extra 2 option will be available.
Hidden Go-Kart Mode
To access the Extra Go-Kart mode play through the championship mode and beat the beginners, middle, and high-speed classes. You should get a new car after the last race you win that is a go-kart and then go to the main menu and the first option that was unlockable will say extra.
High speed mode and more
Enter "2QjD +D1Q 9Fy2 5B0C" as a case-sensitive password to unlock high speed mode, 31 cars, and have all first place wins.
View credits
Go to the screen with "Start" and a picture of the car. Hold L + R, then press Up + B. If you entered the code correctly, you will hear a chime.