Under Cardassian control, all Terok Nor systems underwent periodic systems checks to ensure that equipment and procedures were operating as designed.

    The Starfleet diagnostics run from 1 to 5, with 1 being the most comprehensive diagnostic and 5 being a fast automated scan.

    Following careful study by the Deep Space 9 reconstruction teams, the Starfleet scale was adapted for use on the station. However, the exact protocols and diagnostic scripting routines do not match those in place aboard Starfleet vessels.

    Since the station handover, the systems receiving the most scrutiny by automated monitoring and repair crew are:

* Fusion power plant
* Weapons systems
* Communications
* Environmental control

Level 1 diagnostic- Full automated analysis of system with mandatory crew verification, system off-line for possible disassembly and testing over a period of hours.
Level 2 diagnostic- Automated analysis with moderate crew verification.
Level 3 diagnostic- Auto system checks with minor crew verification over a 10 minute period.
Level 4 diagnostic- Automated systems scan with crew notification in less than 30 seconds.
Level 5 diagnostic- Automated systems check by computer in minus 2.5 seconds.