Check-engine lights, also known as Malfunction Indicator Lamps (MIL), appear for a reason-specifically when an engine is operating outside of its normal emissions parameters. When that light flashes, ...

Onboard diagnostics (OBD) systems have been around since the 1980s and were developed to help limit harmful automotive exhaust emissions. Between 1988 and 1995, U.S.-built vehicles came with what's ...