Prior to the development of on board diagnostics, or OBD, you would not know if your car had a problem until it was too late. On board diagnostics not only created a way of easily figuring out engine problems, but also allowed for the prevention of mechanical issues.
General Motors developed OBD 1 in 1981 as a means of monitoring vehicle emissions. Their system created a computer plug-in for their vehicles that would allow a mechanic to see if the emission system was functioning properly and any errors it may have had during its operation.
OBD1 was required in all vehicles sold in California by 1986 and later became required nationally despite its flaws. Even though the system showed its driver a warning light indicating an issue with the emission system, this light was only temporary, and inattentive drivers could miss that a problem ever occurred. Additionally, this system did not monitor fuel tank vapors and had no standardization.
The Clean Air Act of 1990 mandated that all new cars sold in the United States come equipped with OBD2. The OBD2 system leaves the warning light on until the problem is fixed and provides a standard system for all warning lights as well as for the codes that the diagnostic reader draws from the on board computer.
