There is nothing worse than a vehicle that has the check engine light come on when you are going down the road. Even when the car is replying typically you have to stop and consider if you are doing damage by continuing to drive. Is there something to worry about? Is the light just on for regular maintenance? One doesn’t know when you are just going down the road and if the vehicle is still driving correctly you do not also have any way to guess what is happening. How do you discover what is wrong? You use an OBD II car scanner.