How to Tell if a Car's Oxygen Sensor is Faulty?
2 Answers
To determine whether a car's oxygen sensor is faulty, observe the color of the sensor's tip: a white tip indicates that the oxygen sensor has been contaminated by silicon to a certain extent and needs immediate replacement; a brown tip suggests lead contamination, which also requires replacement; a black tip is mainly caused by carbon deposits, in which case cleaning it thoroughly is sufficient. The ceramic part of the oxygen sensor is hard and brittle, so striking it with a hard object or washing it with strong airflow may cause it to break, preventing the oxygen sensor from maintaining normal working conditions.
As a veteran driver with twenty years of experience, my old Ford Focus once had an oxygen sensor issue. The most obvious warning was the engine fault light on the dashboard—it wasn't just a flicker but stayed lit continuously. The fuel consumption suddenly skyrocketed; where I used to get 500 kilometers on a full tank, I was only getting around 400 kilometers at that time. During acceleration, the car felt sluggish, as if it lacked power. The exhaust pipe also occasionally emitted a foul rotten egg smell, a clear sign of incomplete fuel combustion. I checked the manual, which stated that such symptoms often indicate a failing oxygen sensor in the emission monitoring system. Later, I took it to a repair shop, and they diagnosed it immediately by reading the fault codes with a computer. After replacing the sensor, the light went off, and fuel efficiency returned to normal. So, paying attention to changes in your car's condition is crucial.
