What are the causes of oxygen sensor failure?

[StDaisy]

Oxygen sensor failure is caused by: 1. Ceramic breakage of the oxygen sensor; 2. Burnout of the heater resistance wire; 3. Internal wiring disconnection of the oxygen sensor. The functions of the oxygen sensor are: 1. To determine whether there is excess oxygen in the exhaust after engine combustion; 2. To ensure the high conversion efficiency of the three-way catalytic converter for pollutants in the exhaust. The working principle of the oxygen sensor is: It uses a ceramic sensing element to measure the oxygen potential in the vehicle's exhaust pipe, calculates the corresponding oxygen concentration based on the chemical equilibrium principle, and achieves the purpose of monitoring and controlling the combustion air-fuel ratio to ensure product quality and compliance with exhaust emission standards as a measuring component.

[LukeLee]

I've been repairing cars for over a decade and have seen many oxygen sensor failures. The main causes include sensor aging—since these are installed on the exhaust pipe, the components are prone to wear and tear under prolonged high temperatures, leading to natural failure when they reach the end of their lifespan. Various types of contamination are also common, such as engine oil burning or coolant leaks mixing into the exhaust system and fouling the sensor. Wiring issues frequently occur too, like corroded connectors, short circuits, or open circuits that interrupt the signal. Voltage instability can also damage the sensor, especially if the alternator is faulty and causes battery voltage fluctuations. Additionally, physical impacts, such as hitting a pothole, or internal heater failures can cause problems. When the sensor fails, the car will trigger the check engine light, experience a sharp increase in fuel consumption, and fail to meet emission standards, so it's important to diagnose and repair it quickly. I recommend regular cleaning of the exhaust system as a preventive measure.

[VonJude]

I once encountered the engine light turning on while driving, and the diagnosis showed an oxygen sensor failure. Looking back, it might have been due to excessive carbon buildup, as I frequently took short trips and the engine often started cold, leading to carbon deposits attaching to the sensor. Another time, I drove through deep water, and the wiring got corroded due to water ingress. Sensors themselves can also age, and internal wear over time can cause inaccurate signals. Pollution issues, like engine oil leaking and clogging the sensor's pores, can affect readings. Voltage-wise, a weak battery or loose wiring can also cause problems. When symptoms appeared, the car shook and had poor acceleration, which was very annoying. Fortunately, I promptly went to the repair shop and replaced the faulty part. Now, I avoid short trips to reduce carbon buildup.

[SanErin]

Just got my driver's license, and the check engine light came on. The mechanic said it's a faulty oxygen sensor. The usual cause is carbon buildup covering it, which happened because I often accelerate aggressively. Corrosion in the wiring could also be to blame, especially if connectors rust in humid conditions. Sensor aging simply means it wears out naturally over time. Internal failures, like a broken heater, can prevent the sensor from working properly. Physical damage, such as deformation from hitting a pothole, is another possibility. These issues disrupt the air-fuel ratio adjustment, leading to higher fuel consumption and engine hesitation. I've learned my lesson and now avoid stomping on the gas pedal.