What are the main reasons for oxygen sensor failure?

[McAdrian]

The main reasons for oxygen sensor failure are: 1. During the closed-loop control process where the engine uses the oxygen sensor, the air-fuel ratio of the mixture is always controlled near the theoretical air-fuel ratio, and there is almost no excess fuel in the exhaust. However, immediately after the engine starts, it requires an adequate fuel supply; 2. The chemical reaction between lead ions in fuel or lubricant additives and the platinum electrode of the oxygen sensor leads to a reduction in the catalytic performance of the platinum catalyst, a phenomenon known as lead poisoning; 3. Silicone sealants, silicone resin molded parts, and silicon additives in castings on the engine contain silicon ions, which can contaminate the outer electrode of the oxygen sensor, while the silicone rubber used for sealing at the internal terminals of the oxygen sensor can contaminate the inner electrode.