where is the upstream heated 02 sensor located on 1998 nissan quest?

Question

Hello We are trying to find to the location of the "upstream 02 sensor code PO135" to replace.

Answer 1

HI there

This code is for the bank 1 sensor 1 heater circuit. Typically the problem is the O2 sensor. Bank 1 is the rear bank closest to the firewall, sensor 1 is the sensor BEFORE the converter on that pipe.