2005 Nissan Pathfinder 4.0L with engine code P0420

Question

I'm trying to find out what is going on. The cats were replaced about a year ago. I had a code for bank 1 sensor 1 and bank 2 sensor 2. Replaced both. Bank 2 sensor 2 went away but bank 1 sensor 1 rema8ns. R placed bank 1 sensor 1 again thinking faulty o2 sensor. Now I have bank 1 below threshold code please help

Answer 1

P0420 Catalyst below threshold Bank 1

Depending on the year of the vehicle, the Pathfinder was plaqued by P0420 and on top of that was a timing chain whinning noise. The timing chian guides where upgraded to better timing chain guides, But the fix for P0420 was to replace the catalytic on Bank 1. depending on the year it would be easy to find for any ECM calibration or update.

Answer 2

P0420 Nissan Code - Catalyst System Efficiency Below Threshold Bank 1
Read more: https://www.autocodes.com/p0420_nissan.html