In order to enter a code, it is required that you collect all Enigma Code Collectibles in the game that are necessary for that code. You can find a collectibles guide
HERE.
Code 2:02 04 06 08 01 03 05 07 09
07 05 03 01 08 06 04 02 09
The earliest this can be unlocked is after Chapter 8. This will also unlock "Walk in the Park Mode".