Fuel light on Dash board alight

Fuel lights these days in modern cars come on for more reasons than just having little fuel left in the tank. toyotas electronics are very reliable and not too complex. but this could indicate a couple of reasons 1) the fuel filter in the tank is dirty. 2) the sensor for the fuel capacity is defected. and 3) the wrong fuel is messing about the injector system.
a diagnostic machine should locate the problem very quickly. good luck