That’s a good question, and it’s hard to answer this definitively. If the check engine is on continuously (without flashing), it’s generally safe to continue driving to your destination and make an appointment with a reputable auto repair shop as soon as possible. If you notice that your car is not responding, that the engine “feels” especially sluggish or uncooperative, or if you hear that it’s misfiring or making unusual sounds, you’re probably better off pulling over and calling for roadside assistance.