First thing I always check is the gas cap, if it's broken it can set a fault code which will turn your engine light on. However, most cases it is more than that. The vehicles computer turns the light on because it noticed a problem somewhere in the vehicle. I would suggest to take it to a trained mechanic and they can hook up an OBDII scan tool to your vehicle, which will communicate with your vehicles computer. Once the code is found, there are test procedures which have to be done. If you’d like to try to fix it yourself, your local part store can sell a generic scan tool for $100 and you can look up what the code means online.