Yes, the dealership will buy your car even if it has the check engine light on. However, serious dealerships will try to uncover the reason for the light to illuminate. And if they discover it is due to a serious underlying issue, they’ll use this as an excuse to buy your car at a much lower price. Some folks argue that it’s okay to remove CEL before selling your car to the dealership. However, they’ll still get to know about and this could amount to illegal. The best way to go about it is to have the issue fixed by a professional before selling. Or you should let the dealership know of the issue when selling the car to avoid legal issues for you.