How to Determine if a Car Oxygen Sensor is Faulty?
2 Answers
You can determine if a car oxygen sensor is faulty by observing the color of the oxygen sensor. If the oxygen sensor appears white at the tip, brown, or shows other unusual colors, it may indicate contamination, and the oxygen sensor must be replaced. The color of the sensor's tip can also help diagnose the issue: 1. Light gray tip: This is the normal color of a functioning oxygen sensor; 2. White tip: Caused by silicon contamination, requiring replacement of the oxygen sensor; 3. Brown tip: Caused by lead contamination, and if severe, the oxygen sensor must also be replaced; 4. Black tip: Caused by carbon buildup, which can usually be cleared automatically after addressing the engine's carbon deposit issue.
Last time my car suddenly had a skyrocketing fuel consumption, I almost cried at the gas pump! I immediately connected an OBD scanner and found both upstream and downstream oxygen sensors stuck at 0.45V without fluctuation - they should normally oscillate between 0.1V and 0.9V. The driving experience was even more obvious - it felt like someone was holding my belt when I floored the accelerator, with the engine shaking like an old cellphone on vibrate mode. The exhaust pipe kept puffing black smoke that smelled like burning plastic. Actually, that yellow check engine light had been on for a while, but I ignored it - now I'm kicking myself. A faulty oxygen sensor can really cause trouble, so I recommend checking data streams immediately if you notice abnormal fuel consumption.
