Please take note of the distinction of SHiFT codes from normal 'first party' codes. While normal codes are activated directly through your console's dashboard or through Steam on PC. SHiFT codes however, are activated from within the game through the "Extras" menu options.
The only SHiFT codes that have been released with packaged copies of the game are the "Multiplayer Upgrade Boost" promotional codes. All other pre-order, online pass, activation and DLC codes that have been released with the packaging or printed on retailer receipts should be redeemable through the console dashboard or Steam on PC.
Also note, SHiFT codes require users to create a SHiFT account with Gearbox and be of age 18 or above. For XBox 360 users, you must also have an XBoxLive Gold account.
If you are having issues with Gearbox's SHiFT system (faulty codes, forgotten passwords, etc...), please contact them directly for assistance, as we have no access to this system: