What is I/M Readiness and why is it important?

I/M (Inspection and Maintenance) Readiness shows whether the various emissions-related systems on the vehicle are operating properly and ready for emissions testing. I/M Readiness status indicates which Monitors have completed their diagnostic testing (solid Monitor icons) and which have not yet run (flashing Monitor icons). Before an Emissions Test (Smog Check) can be performed, your vehicle must meet requirements including having no diagnostic trouble codes present and, depending on your area, may require all or some Monitors to indicate a 'Has Run' status.