What are the symptoms of a defective oxygen sensor?
Signs That Your Oxygen Sensor Is Bad
Can a O2 sensor be bypassed?
Should You Bypass Oxygen Sensors? Bypassing the oxygen sensor with a dummy can be done. Many people will do this to get the Check Engine Light to turn off when emissions aren't right or to allow for more flexibility when tuning the engine. via
What happens if the O2 sensor is bad?
When an O2 sensor goes bad, it can no longer trigger accurate fuel injection levels, regulate exhaust gas, or ensure efficient fuel combustion. Consequently, the vehicle may release harmful environmental pollutants or carbon-based compounds – in addition to having subpar engine performance. via