The oxygen sensor is damaged, the fuel consumption of the engine is easy to increase, the exhaust pipe emits black smoke, and the idle speed is unstable. In addition, it is easy to turn off the fire in rainy days, both good and bad, so it must be replaced. Besides, clearing the fault code you said is only a short-term clearing, so that the fault light does not light up. After replacement, you must use a computer to check its working condition. Note that its working voltage is always changing, ranging from 0. 1 to 0.9, otherwise it will be damaged. If there is a decoder, look at the numerical changes.