Computer control systems have complicated the auto repair business over the past 20 years. To repair cars today, general shop equipment is not all you need to diagnose and repair every car that comes through your door. Aftermarket scan tools such as handhelds and PC based interfaces still do not give you complete repair, programming, and diagnosis information. Factory level scan tools give you the most complete information for repairs. Unfortunately the costs of purchasing 10 seperate factory scan tools and maintaining the subscriptions for each is not a plausible shop equipment expense for most repair facilities.