What is OBD and how does it work?
Since the early 1980’s, many vehicles have used electronics and on-board computers to control many of the engine control systems, such as fuel and ignition. Vehicle manufacturers had to develop ways to diagnose problems generated by the new electronic hardware found under the hood. Thus, auto manufacturers developed the first on-board diagnostic (OBD) systems as electronic systems replaced mechanical systems. A more sophisticated on-board diagnostic system was eventually developed, and the second-generation on-board diagnostic system (OBD-II) became required for 1996 and newer vehicles. The engines in today’s vehicles are largely electronically controlled. Sensors and actuators sense the operation of specific components (e.g., the oxygen sensor) and actuate others (e.g., the fuel injectors) to maintain optimal engine control. An on-board computer, sometimes known as a “powertrain control module” (PCM) or an “engine control module” (ECM), controls all of these systems. The on-board comp
