When programmed to run a Basic Reality Check, this device gives a Ship Status Report, which lists all of the ship's instrumentation in green alphanumeric code (A14D, QR18, K17, etc.). The Codes are listed consecutively. Three lights show the status of the instrumentation: green for normal, yellow for standby, and red for malfunction. Malfunctioning parts are also denoted by a flashing text. Systems marked with a standby (yellow) notice should be examined as soon as possible. Malfunctioning systems (red) are partially or completely unusable. A single red light indicate the failure of individual component. But if all the lights on the Fault Locator were to activate it would mean the ship was about to disintegrate. The Locator can also provide the operator with a printout. While the scan takes only 3 seconds, it takes about ten minutes for the Locator's visual display unit to display the status of every instrument on a TARDIS. Operators are cautioned that the Fault Locator can't pinpoint stuck switches or misaligned controls.
The Fault Locator is made of an entire wall of computer banks, found in the Fault Locator Power Room, near the Secondary Control Room. There is also a readout display under a flap on the console. To ensure reliability the Fault Locator operates on a completely different system and has its own power source. The Fault Locator is also used to activate Self-Repair Mode.
The following color code is used:
- Black: For information from the TV Series, including Dimensions in Time, and 1996 TV Movie.
- Blue: For information from the Novels and Audios including Target, Virgin, BCC, and Big Finish.
- Green: For information from 'licensed' reference sources such as the Technical Manual, Doctor Who Magazine, and the Role Playing Games.
- Red: For information from unofficial sources -The Faction Paradox series, behind the scenes interviews, author's speculation, and popular fan belief.
The TARDIS Technical Index is copyright Will B Swift.