After the catalytic converter.
In the exhaust system, before the muffler.
It is located in the catalytic converter
That would be the O2 sensor after the catalytic converter.
Bank 1 catalyst efficiency failure. The catalytic converter has failed.
That should be the sensor located after the catalytic converter.
Nowhere. It attached to the exhaust pipe, not the engine.
That should be the O2 sensor just before the catalytic converter.
To pass emissions you do.
Catalyst efficiency below threshold. (The catalytic converter may be failing.)
Could be a plugged fuel filter or a plugged catalytic converter.
Bank 1 sensor 3 would be the O2 sensor after the catalytic converter.