Nissan Repair Questions? Ask a Mechanic for Answers ASAP
It has been my experince that that code is never resolved with oxygen sensors. I also have experienced multiple times that aftermarket catalytic converters are not strong enough to pass the Catalyst monitor, So they set the P0420. What yo most likely need is a factory cat. Or Try a different brand of aftermarket cat.
What is the year, Make, Model and engine size of this vehicle?
Anything not Made by the original manufacturer is aftermarket. Walker is aftermrket
The code you have is refering to the Precatalytic converter attached to the rear manifold by the firewall. Its about $700 from nissan.
You would normally want the precats to match. Or it may set another code for the bank 2 after you replace the bank1
Im not exactly sure about that