Turn off All Codes? (at least turns off Free Slide, Free Drive and unlock all worlds/locations):

SELECT SELECT START START SELECT SELECT START START X X

Free Slide (within Extras on Main Menu): SELECT A B Y

Free Drive (within Extras on Main Menu): SELECT X X A A B B

Unlock all worlds/locations (must be done before new game, doesn't work with an existing save): SELECT R L R L X X

Gives all clues: SELECT L X L L X

Gives all traps: SELECT L Y R R Y

Gives access to all levels in the world hub (reloading the hub is necessary for scooby's paws to appear): SELECT B B A B B Y