What is OBD anyway ??

OBD is an acronym that stands for On Board Diagnostics. It generally refers to the on-board computer system whose job is to monitor the health of the vehicle. OBD's original purpose was to help control vehicle emissions by monitoring major engine components and alerting the driver about potential problems by lighting the "Check Engine" indicator, also called the "MIL" (Malfunction Indicator Light).

Most vehicles on the road today, are equipped with OBD-II: the second generation of OBD. The key difference between OBD-I and OBD-II is the fact that the latter is more standardized and "open."

The first OBD systems appeared on model year (MY) 1994 vehicles, and starting with MY1996 all cars and light trucks (defined as vehicles with a gross weight of under 8500 pounds) were required by law to have OBD-II.

Over the years, the systems got more complicated. While back in 1996 a typical vehicle supported only a handful of parameters (the jargon word is "PID", Parameter ID), today's vehicles support hundreds of different parameters. Moreover, the OBD bus is no longer used just for diagnostics. Devices ranging from radios to comfort control systems to power locks and windows can be controlled via the OBD bus.

While all this complexity may seem daunting, the fact is that OBD makes repairs cheaper and easier, by helping pinpoint the location of the problem -- sometimes even before it happens. Today, anyone can afford a sophisticated scan tool and get access to information previously available only to dealership technicians.

Two of the most popular scan tools on the market are OBDLink andElmScan 5. They are easy to set up and use, and are compatible with more diagnostic software than any other scan tool. Among other things, you can use a PC-based scan tool to read and erase trouble codes, view and graph live data, and even create digital dashboards.