VOY Manual · Chapter 2 · A Technical Introduction
2.13 System Diagnostics
Explains the standardized, pre-programmed system diagnostic procedures of varying levels used to investigate trouble in shipboard systems.
In brief: When trouble is suspected in a shipboard system, our crew will often perform a number of standardized procedures called “system diagnostics.” Most key systems have several pre-programmed diagnostic programs, ranging from a “Level One Diagnostic,” which can take several hours to perform, to a “Level Five Diagnostic” which usually takes just a few seconds.
How to use it: A senior officer (like the chief engineer) will usually order something like: “Perform a Level One diagnostic on the transporter system.”