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 4:04 08 03 07 02 06 01 05 09
05 01 06 02 07 03 08 04 09
The earliest this can be unlocked is after Chapter 16. This will also unlock "Ironman Mode".