I've often thought about why there aren't any diagnostics manual on a very broad level, a counterpart to the medical DSM-IV/ICD-10 manuals. From a troubleshooting perspective, the work of an investigative technician would be very much a like that of a physician: Gather information about the problem, investigate root cause and diagnose, provide information as to why the problem has occured, what is normal behavior and resolve it.
I would assume that a computer technician has better capabilities of understanding an IT problem since we've created computers and have defined how they should work (unlike medicine, which we're still learning many fundamentals of). If this assumption is correct, I imagine that it's possible to write such a manual that would also be very precise/exact.
So my thoughts are: Would it be beneficial to compile such a manual? Are there any obvious problems I've missed that makes this an impractical idea? Why haven't this already been done?