Is my vehicle ready for an emissions test (smog check)?

A GREEN LED after code retrieval indicates all monitors have completed their diagnostic testing and there are no DTCs present, meaning the vehicle is likely ready for an emissions test. A YELLOW LED means a pending code or incomplete monitors may be an issue depending on your local emissions regulations. A RED LED means the vehicle is not ready — the underlying problem causing the DTC must be repaired before an emissions test can be performed. (Page 24–25)