<b>3.)</b> Our initial problem with our Ford Explorer was a "check engine" light coming on, and not having the wherewithal to deal with it. We knew it could mean nothing important, but the glowing amber usually indicates a faulty component. The OBD systems on today's vehicles monitor many emissions, ignition, and fuel systems. Better mileage, more power, cleaner air, and reduced risk of damaged parts are all possible by keeping your rig in top shape, and a scanner can help do that.