08-04-2009, 06:45 AM
In the automotive context On-Board Diagnostics, or OBD refers to a vehicle's self-diagnostic and reporting capability and presents the vehicle owner or a repair technician with state of health information for various vehicle sub-systems. Earlier systems of OBD could simply illuminate a malfunction indicator light, or MIL, if a problem were detected--but the nature of the problem could not be specified.
But by the introduction of on-board vehicle computers in the early 1980's, which had made OBD possible the amount of diagnostic information available has had dramatic changes. Modern day systems gives diagnostic trouble codes, or DTCs, which allows one to rapidly identify and fix malfunctions within the vehicle and all this is possible due to the use of standardized fast digital communications port which provide abundant realtime data.
http://qrg.northwestern.edu/papers/Files...Models.pdf
http://teamqsidoc/autotestcon97.pdf
