What Is OBD ?

What is OBD ?

OBD stands for "on-board diagnostics," a computer-based system built into all model year (MY) 1996 and newer light-duty cars and trucks. OBD monitors the performance of some of the engines' major components, including individual emission controls. The system provides owners with an early warning of malfunctions by way of a dashboard "Check Engine" light (also known as a Malfunction Indicator Light or MIL, for short). By giving vehicle owners this early warning, OBD protects not only the environment but also consumers, identifying minor problems before they become major repair bills.

For example, by identifying a relatively inexpensive repair like the replacement of a malfunctioning oxygen sensor, OBD can save the owner the cost of replacing the catalytic converter later. By helping to ensure that the vehicle operates within its original design specifications, OBD can help save consumers money by making sure gasoline isn't wasted as a result of, for example, a loose gas cap or incomplete combustion. OBD stores information about the malfunction detected and actually helps the repair technician to diagnose and fix the vehicle. When OBD checks are performed as part of a state's Inspection and Maintenance (I/M) program, they can help save consumers time, taking on average five minutes or less in centralized programs.