Catalytic Converter code question (2012 CX-9)

[adamsgirl38]

Can the O2 sensors make the catalytic convertor code appear on diagnostics?

 

[yrwei52]

How many miles on your 2012 CX-9?

I assume you’re talking about the infamous P0421 DTC: Warm Up Catalyst Efficiency Below Threshold (Bank 1).

It’s possible bad O2 sensors trigger the P0421, but not likely on high mileage vehicles. The catalytic converter is simply reached its service life. Many would try replacing O2 sensors first as it’s relatively cheaper to do than replacing the catalyst converter with reputable one when they got the P0421, but most found that’s a waste of money. Your 3.7L V6 should have 4 O2 sensors and 2 catalyst converters and 4 good Denso O2 sensors are quite expensive. And if I remember it correctly, 2 upstream O2 sensors are difficult to reach. It’s your decision what you should do, but most likely it’d be costly to get rid of the P0421 code.

 

[yrwei52]

You may try those catalytic converter cleaners but most likely they won’t work and just waste your money.

 

[cz5gt]

the secondary o2 can yes. Thats its only purpose, but usually it just tells the Cat is going bad.
The primary o2 is for the fuel mixtures.
Cats can be cleaned but have to removed from the car for that to be efficient.