i had this car 3 years and since year 1 I’ve been getting P0420 codes catalytic converter. I had been clearing codes and using cat cleaner to get through emissions. Well I came into some extra stimulus and did a aftermarket cat engine back with all brand new exhaust. New sensors (Chinese). Now I get P0030 codes and because I pulled battery cables off within 100 miles of emission test I failed. I get 60 days to sort problem out and two try’s at emissions. 178,000 miles. I’m going to test power and ground to sensor (heater) next. I have to replace cable end it’s loose maybe my problem. Any ideas? Should I have dealership reflash my computer for updates or is car to old for that?