Since 1996, the OBD2 System Has Enabled Drivers to Diagnose the Check Engine Light, Read Live OBD Data, and Much More. OBD2 (or OBD-II) is short for On-Board Diagnostics version 2. It is an electronic system built into your car that constantly monitors engine performance and emissions. Through a variety of sensors, this system can detect problems and alert you to them by turning on the Check Engine Light. By using an OBD2 scanner that plugs into the OBD2 port usually located under your dashboard, you can get detailed information about your car problem from this system. Originally intended for