Question

2004 Nissan Frontier XE 2.4L I'm trying to troubleshoot the code P0420. Could the O2 sensor cause this?

Answer 1

Hi there,

A faulty rear O2 sensor can cause this code, however the only method you can use would be a scan tool that can read live data from both sensors. This way it can be determined if the sensor is working or the converter.

Answer 2

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