Today’s modern vehicles come equipped with an onboard computer diagnostic system (OBD) that monitors your vehicle’s operations at all times. The OBD system continually analyses the status of the vehicle’s exhaust system, gas tank, transmission and many other components.  If a problem or fault is detected it triggers the check engine light to come on to warn the driver or the issue. If something’s going wrong with your car or engine, your onboard computer can tell you about it. If the computer senses something is wrong with one of your car’s systems, it will turn on a dashboard light, like “ABS Brakes” or something less specific, like “Check Engine.