Hello

I have Lexus es300 model 2000, I have removed cat,
The check engine light came on, it's OK.

But after removing the cat I used torque application to see the code, it's same but O2 sensor is working (green)

But now, when I check the sensor by the application I see it's not working (red)

Does anyone know where is the sensor bank 1 is located?

The code is p0420

Is it before or after the cat?