Honda Accord check engine light illuminated with potential catalytic converter or O2 sensor issue on Honda Accord

Some Honda Accord owners report experiencing issues when the check engine light illuminates with a diagnostic code of P0420, which typically indicates a problem with the catalytic converter's efficiency. Symptoms may include decreased engine performance and reduced acceleration, prompting concern among owners. While a faulty catalytic converter is often the primary cause of this code, some owners find that other factors, such as damaged spark plugs, faulty oxygen sensors, or exhaust leaks, could also contribute to the issue. It is crucial for owners to use an OBD-II scanner to check related diagnostic trouble codes and conduct a thorough diagnosis to accurately identify whether the problem lies with the catalytic converter, the O2 sensor, or another source. Addressing these concerns promptly can help resolve the check engine light issue effectively.