Diagnostic tools identify symptoms not fixes,, for fixes you need experience on the vehicle and basic intuative skills at troubleshooting.
Example the average OBD2 car has up to 20 or so codes that say O2 sensor. Guess how many actually identify that its really bad? Exactly 1. And even it iis suspect because it can jut be a bad connector. Want some pure entertainment as your mechanic what he thinks of Autozone scanning codes. Dont stand too close and buy him a beer first... LOL