Flashing or reprogramming your engine’s computer keeps it up-to-date and operating properly. The engine control unit (ECU) is a computer that controls all of your vehicle’s electronic systems. Like many computers, it occasionally requires reprogramming of its operating software. Your vehicle’s warranty may covered it, but there’s usually an additional charge. For example, Mazda charged a fee to re-flash the system so their vehicles could operate Apple CarPlay or Android Auto. On occasion, other vehicles revert to limp-home mode following an ECU malfunction. In order to diagnose what needs to be done, a dealership technician will connect a computer to the vehicle’s On-Board Diagnostic II (OBD-II) port. Consult with your dealership service department for more information on your specific car, truck or SUV.