There are numerous potential causes for a check engine light to illuminate, ranging from minor issues to more serious problems. Some common causes include: - Faulty oxygen sensor - Loose or damaged gas cap - Malfunctioning catalytic converter - Misfiring engine - Faulty mass airflow sensor - Issues with the fuel system (e.g., fuel injector problems) - Electrical system faults (e.g., faulty wiring or connectors) - Emissions control system malfunctions - Engine vacuum leaks - Exhaust gas recirculation (EGR) system issues