I purchased my ES330 with 50,000 miles. Not long after the VSC / Trac Off / Check Engine lights came on. About a week later they went off on their own. This repeated itself in approximately one year intervals, usually during cold weather. Recently the lights came on and stayed on. The Toyota dealer read the P0420 code and recommended that the A/F Ration Sensor on Bank 1 be replaced. They mentioned that if this did not fix the problem, then the catalytic converter would have to be replaced. Replacing the A/F sensor did not fix the problem. I would expect that if the cat converter were bad, it would not be an intermittent problem.
I have seen this topic come up many times, but not for an 2005 ES330. This is why I am starting a new topic. Based on what I have seen on LOC, the problem is right up there with the "transmission hesitation" problem. Also I have noticed that the problem seems to be more prevalent on Bank 1?
Is there any update information on this topic?
