Press 'Select' at the main menu to access the 'Enter Code' screen to be able to input the following codes to enable their effect in the game. To disable some of these codes you must reset the game data at the 'Options' menu.
Unlock ALL Teams: Enter ALL4ME
Unlock ALL Tracks and Cups: Enter CUPIUP
Max. Upgrades for ALL Cars: Enter BIFFIN
Low Gravity: Enter LOGRAV
Weird Sound Effects: Enter IAMCAR
Combines the Effects of ALL the above Codes: Enter BIGUNS