We have to assume along with the Fuel Level Low light, your Kia's check engine light is illuminated as well. Having a trouble code present in the ECU (engine control unit), along with an illuminated check engine light will cause your Sephia to fail the smog inspection. Even though the trouble seems not to effect engine emissions, the check engine light being ON will cause your car to fail the smog test.
Two common problems which could cause a Fuel Level Sender trouble code are having a shorted or open fuel sender circuit or damaged fuel level sending (sensor unit) unit itself. Less likely is the possibility that the ECU or fuel pump computer module has failed. Testing the fuel level sending unit directly will reveal the fault.
