into less polluting substances. If it is damaged, your X5 will not run correctly and the service engine light will come on. It is designed to work with a properly functioning converter, and has sensors to make sure it is working. They are part of the exhaust system, and looks like a muffler, but they are before the real mufflers in the exhaust pipes. Gasoline never directly touches the converter unless it is unburnt gas after the engine fires the gas in the cylinders. This is why low fuel in the gas tank shouldn't harm a converter. Fuel must pass through the engine first.