In some vehicles a low fuel level can cause a check engine light to come on but not in all vehicles.
Some vehicles have a low fuel level light that will come on when your fuel level is low and you will know if your fuel level is low by seeing the fuel gauge drop to near empty.
However if your check engine light comes on when the fuel level drops and then goes out when you put more fuel in the gas tank then that could be the cause of the check engine light.
Even a loose gas cap or a bad gas cap that is not sealing properly can cause a check engine light to come on.
Other causes of a check engine light can be bad ignition coils, bad spark plugs, bad spark plug wires, bad distributor cap and rotor, timing belt stretching etc.
You can take your vehicle to Autozone or Oreilly Auto and they will test your check engine light for free and let you know what is going on with the vehicle to cause the check engine light to come on.