Depending upon the age and mileage of your vehicle, it is possible that failed emissions test components are covered under the original manufacturer’s warranty.
Check your owner’s manual to see how your vehicle may be covered beyond the regular warranty. Federally-required emissions-control warranties may cover emission-related failures that result from a manufacturer’s defect in workmanship of that cause your vehicle to exceed federal emissions standards. For some vehicles, the coverage may be as much as eight years or 80,000 miles.
If your vehicle’s emissions control system was the subject of a recall, you must have the recall work performed prior to presenting your vehicle for emission testing or you may be denied a test.