The codes for cat effiency are either a P0420 or P0430 depending upon which side is showing defective.What you need to do now is to make sure that the cat is the problem and not the rear oxygen sensor.most exhaust shops can check the cats for free and give you an estimate if you need new ones.With the year of you car I would suspect that you may need new cats.Good luck with the repairs and please let me know if you need more assistance,don
Thank you Don for replaying my question.
I have an appointment tomorrow with Meineke to check.
I appreciate your suggestion.
have a great day!!!