There have been multiple problems with these codes and the catalytic converters and updates for the computer under a service campaign as you already know. Toyota by their own policy is obligated to repair or replace any work that they do for one year and I believe unlimited mileage but it may be 12,000 miles you need to inquire about that specifically state. You should not be paying any diagnostics or check out charges for this. I would not buy that they're telling you to go buy a new car they need to stand behind the quality of their parts or they will have to continue to replace the parts at no cost to you because of their own written policy. There is no way around what's causing these codes. It is a computer/converter problem in some cases I have seen the AFR sensors screw up along with the oxygen sensors but normally you will see the those codes along with these converter codes also. There's no magic answer here for this problem. As far as passing the North Carolina emissions I do not know the specifics of their emissions testing. I do know that some states if you pull the negative battery cable to clear the system and drive it directly to the testing center and they run the car on the dino rollers and test the emissions it probably still will pass the emissions testing because of the efficiency of the engine. They may try to tell you something along the lines that the system has not run its readiness test or past its readiness test just tell them that you've had recent work and run the car on the Dino and do the emissions test. Good luck,
I understand that you said Toyota will not pay the claim but if I'm reading the dates correctly the time was less then a year between each occurrence is this correct? If that is the case then have you asked them about why it is not covered for one year? Just for the record I was not implicating that you should try and beat the system I was telling you that the vehicle probably will pass emissions testing on a dino roller due to the efficiency of the engine in the interim so that you can get the converter issue resolved with Toyota.
You did not specify that you wanted the expert who goes by Peter. Good luck I will opt out and notify him.
I recieved a message from Skyvisions to look at this one, aside from the fact that he does not live in NC and is not familiar with the exact emission testing procedures of your state he is by far one of the best expert on this site and one of the most experienced and knowledgable in the Country, there is no need to request my input and assistance on this one, best of luck to you.