Mercedes-Benz C250 not passing smog due to fuel system and oxygen sensor issues on Mercedes-Benz C250

Some Mercedes-Benz C250 owners report experiencing difficulties passing smog tests due to fuel system and oxygen sensor issues. These problems can stem from clogged fuel filters or malfunctioning fuel injectors, which may disrupt the fuel-air mixture and lead to excessive emissions. Additionally, a faulty oxygen sensor can provide inaccurate readings, further contributing to emissions that do not meet smog requirements. Some owners find that driving the vehicle under specific conditions is necessary to reset readiness monitors after addressing these issues. It is recommended to seek a professional diagnosis and repair from a qualified mechanic or Mercedes-Benz repair shop to effectively resolve these concerns. Regular maintenance, including timely replacement of fuel filters and oxygen sensors, is also crucial in preventing future smog-related problems.