Catholic Scanner aims to check whether certain doctrines are present in an understanding of the Catholic faith by asking a series of questions. All questions are in the form of "true or false". They are presented in two ways. Firstly, via a "Quick Scan", where ten questions are posed checking for the most common doctrines. This takes only a few minutes. If the player exits this mode, the questions are reset. The second mode takes the form of a "Deep Scan". In this mode, many more questions are posed, which check for more obscure doctrines which may be held by the player. The questions posed in this mode persist if the player leaves the application, meaning the a "Deep Scan" can take place over a number of sessions. When a doctrine is found, in either of these modes, it is placed into the Vault, access to which is found in the Main Menu. The Vault icon is either green, indicating that there are no doctrines present, or red, indicating that certain doctrines have been found and placed in the vault. To empty the Vault of its contents, it is necessary to enter the Vault by clicking on the button in the Main Menu, and selecting one of the doctrines listed there. The player will then be required to read about that doctrine from a Catholic perspective for a period of time. This will remove that doctrine from the Vault.
