How Often Should the Front and Rear Oxygen Sensors Be Replaced?
2 Answers
If the oxygen sensor is not faulty, it does not need to be replaced. Methods to check if the oxygen sensor is damaged: 1. Unplug the wiring harness connector of the oxygen sensor to disconnect it from the computer, putting the feedback control system into open-loop control mode. 2. Connect the positive lead of the multimeter's voltage range directly to the feedback voltage output terminal of the oxygen sensor, and ensure the negative lead is properly grounded. 3. Measure the feedback voltage while the engine is running. First, disconnect the crankcase forced ventilation tube or other vacuum hoses connected to the intake manifold to artificially create a lean air-fuel mixture. Observe the voltmeter—the pointer reading should decrease. 4. Reconnect the disconnected hoses, then unplug the coolant temperature sensor connector. Replace the coolant temperature sensor with a 4-8KΩ resistor to artificially create a rich air-fuel mixture. Observe the voltmeter—the pointer reading should increase. 5. If the oxygen sensor's feedback voltage does not show the above changes, it indicates that the oxygen sensor is damaged.
Recently, my car had an issue where the engine warning light kept staying on. After taking it to the repair shop, it turned out the front oxygen sensor was dead, costing me over 600 yuan to replace. I remember the veteran mechanic saying these sensors typically last about 80,000 kilometers, depending largely on your driving habits and fuel quality. If you frequently drive in stop-and-go city traffic or use poor-quality gasoline, the sensor can easily get carbon buildup or become poisoned, leading to early retirement. After the replacement, fuel consumption has noticeably dropped, and the exhaust doesn’t smell as pungent anymore. I recommend setting a mileage checkpoint—like scanning with an OBD diagnostic tool every 50,000 kilometers—instead of waiting for a real failure to occur, as it significantly impacts the car’s fuel efficiency and emission control.
