What is the meaning of a yellow engine outline symbol (luz de anomalia do motor / Check Engine) illuminating steadily on the dashboard during driving?

1. The engine management electronic control unit (ECU) has detected an emissions, sensor, or powertrain malfunction requiring diagnostic inspection
2. The engine has run out of petrol completely
3. The vehicle needs to be driven at maximum speed to clear the exhaust
4. The engine oil level is at maximum