Explain the role of a catalytic converter and how a faulty O2 sensor can impact emissions and fuel economy.

• A. Catalytic converter converts harmful exhaust gases to less harmful substances; a faulty O2 sensor can cause incorrect fuel trims, resulting in rich or lean mixtures, higher emissions, and reduced fuel economy.
• B. Catalytic converter increases exhaust noise to improve performance; a faulty O2 sensor has no effect on emissions.
• C. Catalytic converter stores oxygen to reduce emissions; a faulty O2 sensor improves fuel economy.
• D. Catalytic converter filters oil vapors; a faulty O2 sensor directly improves power output.

Answer: (A)