Cars are incredibly complex systems that interact to keep the engine running efficiently, the brakes working perfectly so they can stop the car at any moment and the emissions system operating to keep the vehicle’s exhaust in check.
In 1970, congress passed the Clean Air Act, requiring automobiles to meet a 90% reduction in their emissions. The Environmental Protection Agency began monitoring emissions and requiring controls on vehicle emissions, bringing about the birth of ERG (exhaust gas recirculation) valves and the catalytic converter. Accomplishing the Federal mandate also led car manufacturers to develop the on-board diagnostic (OBD) system in the 1980s to electronically manage the vehicle’s components and output electronic trouble codes.
Today when a car diagnostic tool emissions test is necessary, an OBD2 scanner reads codes from the car’s monitoring system and displays a series of codes. Many of the OBD scanner codes can be interpreted into text so anybody can read the error. Dealerships have the biggest advantage because the scanner devices used in the shop have all the factory codes listed and cross-referenced with the possible solutions for the problem.
Anyone can use an OBD2 scanner. The average Jane Doe mechanic can buy a good unit for around $100 and quickly hook up to almost any post 1966 vehicle; few if any vehicles have on-board diagnostics before this date. With a companion volume of codes and diagnostic information, it is fairly straightforward to get an idea about why the check engine light is on for example. Manufacturers do not always publish all the codes and the details behind them, but you can still view an outline of the troubled vehicle.
These car scanners have a lot of other features as well. Some can reset the check engine light, which a dealer charges to perform, even if the problem has been fixed. Accessories also allow the units to test batteries, perform emissions and electronics tests and continuously scan for new codes.