On-board diagnostics (OBD) is a term referring to a vehicle's self-diagnostic and reporting capability. In the United States, this capability is a requirement to comply with federal emissions standards to detect failures that may increase the vehicle tailpipe emissions to more than 150% of the standard to which it was originally certified. [1][2]
A car repair resource site that helps you diagnose vehicle OBD, OBD-II, and OBD2 problems. We have many articles on how to diagnose and repair many check engine light codes.
The OBD port is an electrical plug that OBD-II scanners, code readers, and other devices can be plugged into to access the OBD-II system. It is also the port that is typically used for state vehicle inspections.
Look up any OBD-II trouble code instantly. Get plain-English definitions, causes, fix costs, and step-by-step repair guides written by ASE-certified mechanics.
OBD Code Lookup Tool — Search Any DTC Code | OBD Advisor
On-Board Diagnostics (OBD) is the built-in system in modern vehicles that monitors engine health, emissions performance, and overall drivability. If you’re trying to understand a Check Engine Light or diagnose a rough idle, OBD is how your car “tells you” what it sees—through codes and live data.
OBD, or on board diagnostics, was introduced by General Motors in 1981 to monitor the emission control system in the car. In 1986 California mandated that all cars sold in the state be equipped with OBD, and it became the industry standard.
On Board Diagnostics (OBD): What Is It and What Does It Mean to You?