What are the causes of oxygen sensor failure?
2 Answers
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.
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.
