How to Tell if Your Oxygen Sensor is Faulty?
3 Answers
You can determine the condition of the oxygen sensor by observing its exterior color. A normal sensor tip should be light gray in color. If it appears white or brown, replacement is necessary. Below are some precautions for using an oxygen sensor: 1. Drive smoothly whenever possible: Unless in emergency situations or poor road conditions, try to minimize severe shaking or impacts to the vehicle body, and avoid scraping the undercarriage (especially near the exhaust pipe). The oxygen sensor contains ceramic sensitive elements, which could be damaged by severe shaking or impacts. 2. Pay attention to the sensor wiring: During routine vehicle maintenance, avoid excessive pulling of the wiring. Like other electronic devices, if the wiring of the sensor is affected, leading to unreliable connections, it may interfere with the normal operation of the oxygen sensor.
Recently noticed my car is consuming significantly more fuel, nearly 2 liters extra per 100km compared to before. The fuel gauge drops rapidly after just 300km of driving. The engine feels sluggish, lacking its usual punch when accelerating from traffic lights, and the car occasionally jerks inexplicably at low speeds. Last week at the repair shop, diagnostic scan showed fault codes indicating abnormal fluctuations in the rear oxygen sensor. The mechanic said emissions exceeded standards, with a pungent acidic smell from the exhaust. Many drivers overlook this component, but when faulty it can silently increase fuel consumption by 20% and will definitely fail emissions testing. These sensors typically last about 80,000km - best to proactively check them after exceeding 100,000km.
A common issue when the dashboard warning light comes on after prolonged driving is a faulty oxygen sensor. The other day, the engine's yellow warning light turned on, and the tachometer needle suddenly fluctuated up and down at idle. Throttle response was particularly sluggish. I checked the values with an OBD scanner and found the front oxygen sensor voltage stuck at 0.45V without any fluctuation, while it should normally vary between 0.1V and 0.9V. The inside of the exhaust pipe was covered in black soot, and the exhaust smelled heavily of gasoline, as if I had just refueled. It's recommended to test it on the highway—under normal conditions, the warning light should turn off after driving at 80 km/h, but mine stayed on for three days without going away. A faulty oxygen sensor not only damages the catalytic converter but will also definitely cause the car to fail emissions testing.
