When the first automobiles were designed, they were simple machines. When an early vehicle would break down, you didn't need a car scanner, all that would be required is knowledge and a few simple tools to perform the needed repairs. The basics of any internal combustion engine were simple. The engine needed air, gas and timing to make a simple explosion inside of the engines cylinders which is called combustion.
This combustion is what produces power for the engine to move the vehicle. If any engine didn't have one of these, it wouldn't run and therefore by knowing why it didn't have a necessary component, one could fix that one item and the engine would be running smoothly once again.
These basics of an internal combustion engine remain the same. The difference with the earlier engines and today's engines can be summed up by saying that today's engine are simply more advanced. Having the knowledge and a few simple hand tools may not be enough to get an engine running smoothly again.
The need for better fuel economy, less emissions and the comforts of today's automobiles requires more computer components than ever before. For these reasons, a car scanner is a much needed and utilized tool in today's mechanics tool inventory.
A car scanner can simply be plugged into a cars computer jack that is normally located under the dash on the driver's side of the vehicle. Once this tool is plugged in and operating, it communicates with the car's computer system and relays information back to the mechanic. This information is converted inside of the scanner to show an "error code" that then can be identified to the mechanic what is malfunctioning within the vehicle. Without this important tool, a mechanic would be simply "guessing" at the problem with the vehicle. This tool identifies the problem and tells the mechanic exactly the parts that need to be replaced.
Even though this tool takes much of the guess-work out of vehicle repairs, it still requires much knowledge of the vehicle being work on. The scanner with flash the code which can vary from model to model and the mechanic needs to understand what the code actually identifies. The same code could flash on two different model cars and necessary not mean the same malfunction. This is the kind of knowledge that the mechanic needs to have a thorough understanding of.