I have a 2000 ES 300 with 150K. My check engine and Trac Off light came on simulataneously while driving down the highway. The code that the dealer gave me was P0446 which he said meant that I needed my Bank 1 catalytic converter replaced (for a cost of $1700). From the other postings that I'm reading regarding this code, I don't see anyone mention replacement of the catalytic converter. Does this seem like a reasonable fix? I've previously had the mass air flow sensor replaced when I had the check engine/trac off lights come on about 2 years ago. After that replacement, all was well until now. Any advice would be much appreciated! Thanks.