Set a record (Best Lap, Best 3 Lap, Most KO's) and enter "NO TIME" on the name entry screen. This will enable cheat mode. The following codes may now be activated:
After enabling cheat mode go to the main menu and hold L1 + L2 + R1 + R2, then quickly press Right, Left, Right, Left, Circle, Square, Circle, and Square.
All Art Galleries
After enabling cheat mode go to the main menu and hold L1 + L2 + R1 + R2, then quickly press Right, Square, Left, Circle, Down, X, Up, and Triangle.
After enabling cheat mode go to the main menu and hold L1 + L2 + R1 + R2, then quickly press Triangle.
Repair without Losing Speed
Hold R2 + L2 during a race to get repaired without having to lose speed.
Unlock all the tracks and then play with any racer in versus mode. To unlock Sebulba, defeat player two and then the race you did not get a racer on to unlock it. To unlock all the extra racers, win every race in first place with any character.
Race as Anakin (Episode 1)
To unlock Anakin, get the fastest track time on every track.
Race as Darth Maul
To unlock Darth Maul, get the top KO score on every track.
Race as Watto
To unlock Watto, get the three fastest lap times on every track.
Race as Darth Vader
In order to unlock Darth Vader you must unlock Anakin, Watto, and Darth Maul, then win a tournament with one of those characters.
Race as Sebulba
To unlock Sebulba, win all three tournaments as Sebulba.
Complete the tracks in tournament mode to unlock them in the other modes.