Q: Smog check failed due to Oxygen sensor

Hello, thank you for writing in. The first person to tell you this was correct to a certain extent. If the system is not warmed up, the readings cannot be taken accurately. However, if the engine is warmed up and the system is still not reading correctly, you may have an issue with the oxygen sensor or the engine. If you have a warning light or an OBD-II code of any kind, you must resolve that issue before retesting. The issues can stem from misfiring issues to fuel problems. Only further testing will tell. For more help with diagnostics or repairs, contact our service department to schedule an appointment.