The latest on board diagnostic system OBDII has a number of advantages over the previous system, one of them is the ability to warn of an impending failure. If a sensor, relay, or valve etc. that is monitored by the ECM begins to occasionally malfunction but is still working the majority of the time, the computer will log a diagnostic code. A good way to deal with that kind of fault code is to clear it from the ECM and see if it reoccurs. If it logs the same "intermittent" or "impending failure" code, there is most likely a real problem with the part an it should be replaced before it totally fails.
A lot of folks don't like the system, but personally I love it. OBDII makes diagnosing problems much easier than the old days of each manufacturer having their own unique system. That's why every car and bike have the same plug-in now.