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..
When you turn on the ignition, the "Service Engine Soon" or "Check Engine" light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the environment!
If the light comes on and stays on, the OBD system has detected
a problem. Your vehicle might have a condition that wastes fuel,
shortens engine life, or causes excessive air pollution. If left
unaddressed, these conditions could also damage your vehicle and
lead to increasingly expensive repairs. For example, OBD can
identify a loose or missing gas cap (which wastes fuel and
contributes to smog) or engine misfire (which can lead to severe
or permanent engine damage).