When the automobile first appeared towards the end of the Nineteenth Century, they were designed to allow the owner access to perform basic maintenance and simple repairs. While some areas such as the engine were more complex than most people may have been familiar with, large parts of these first cars were no complicated than the buggies and coaches that were a part of daily life. And with the exception of a major mechanical failure, even the engine soon held no mystery for enthusiastic car owners, many of whom soon found great enjoyment with tinkering under the hood. The great love affair with the automobile had begun.

By the middle of the Twentieth Century, whole generations had grown up with the car as a part of daily life. As the pace of technology increased, so too did the automobile. Faster, more powerful engines appeared, and the various subsystems evolved to meet the changing demands involved. Autos became bigger, heavier and more and more time was spent driving. This in turn led to more concern over the environment inside the car, and the comfort and safety of the driver and passengers. While many people continued to do much of their own upkeep and repairs, more and more often the specialized ability of the garage mechanic became the preferred way to keep their cars functioning. The popularity of 'shade-tree mechanics' or a family member with a knack for motors were also helpful for people who were increasingly unable to deal with the increasing complexity of their own automobiles.

Now in the Twenty-First Century, computers have become a standard item in every car. They constantly monitor, control and analyze the condition of most of the major systems throughout the automobile. These onboard computers can be connected to external diagnostic systems that can interpret and report on the health of the engine, brakes, electrical systems and many other components. For a time, these complex machines were only available to a few garages, but computing power has increased while prices have fallen, and they are now available to anybody as hand-held units with more computational ability than large mainframes a few decades ago. Another byproduct of the computing age is to reduce shelves of bulky repair manuals to a small stack of CD-ROMs. As our cars continue to evolve to meet the challenges of the future, diagnostic tools and software will play an ever more important part of maintaining them at peak efficiency.