Bugger, the post I've is around the pretty quite early UK aw11 ecus which didnt seem to operate a cat more than in britain, so no more details about exactly what the O2 sensor does in this article. That is what the resistor pack on some versions of the 4AGE https://manuelwcegf.bloggerswise.com/32992418/the-fact-about-toyota-4age-for-sale-that-no-one-is-suggesting