The introduction of computerized diagnostics dates back to the early 1980s with the introduction of on-board computers in vehicles, contained in the first units implemented.
Early versions simply turned on an indicator light in the event of problems, but did not provide any further information regarding the nature of the problem. Modern OBD implementations use a digital communication port to provide real-time information in addition to a reporting of the nature of the problems via standard Diagnostic Trouble Codes (DTCs) that allow for rapid identification and resolution of vehicle malfunctions.
Successive evolution occurred in the 90s of the last century when OBD-II was introduced in the USA.