Diagnosis is the process of determining the system health from observed effects. Typically, over 50% of the cases, the corrective action can be diagnosed unambiguously by reasoning on the presence and absence of error codes. For those cases, troubleshooting can be completely eliminated. For the rest, the diagnosis from observed effects reduces the list of suspects to a small set, and the reasoner can generate an optimized sequence of (troubleshooting) steps to identify the corrective action.
This is contrast to the traditional troubleshooting practice, which relies on past case history to identify a list of possible corrective actions that the service agent should try until problem appears to be fixed.
With TEAMS, even an inexperienced service agent can find and fix problems as well as an expert!