Oxygen sensor for the 2TR problems, only use Denso

To each his own, but I typically like to replace upstream/precat O2 sensors after 150k miles on my cars. In my opinion it keeps cars running better longer. But that’s a subject for a different thread. But whether you’re replacing it for maintenance or because of a faulty problem this information pertains to you.

I wanted to share some recent findings that the Denso O2 sensor is the way to go. I initially bought a NTK sensor, the shape of it was different but NTK is a well known Japanese brand and the O2 sensor was made in the US so I threw it on anyways thinking all was well from our beloved NGK company.

long story short I kept getting P2195 check engine codes. I initially saved $20 just to spend an additional $130. The denso one looks just like the factory one and has been working flawlessly. When looking at the engine data the NTK seemed to be switching fine, with the o2 voltage graphs looking pretty normal, but I’m guessing there was something about the values the ECM didn’t like, or maybe it was hanging in the lean side ever so slightly too long. It’s possible I got a defective one. I was personally thinking that since the shape and inlets are different, it was registering the signal slightly differently. With modern day emissions and strict parameters this might be enough to upset the ECM.

 

Thanks Sep1911 I'm sure this information will help a lot of us.

 

I agree replacing the upstream/precat O2 sensor(s) after 120-150k miles in combination with 60-90K spark plug changes = top fuel economy, engine power and no worries about getting the dreaded P0420 catalyst system inefficiency below threshold check engine light.

 

Hey all, newbie here. I’m in Wisconsin and a California 2006 i4 appeared in my town and I jumped on it. It has the code coming up for the upstream O2 sensor. We replaced it and still the code comes up. Sometimes downstream as well. The Catalytic that was on the truck was a California one that was clogged and so we replaced it with a “Midwest” catalytic. Wondering if there is a programming change that has to be made when the exhaust is changed in this way? Ever heard of that? We’re just trying to chase down how to get the engine light to calm down! Haha. Any thoughts.

 

What are the codes?

 

I don’t know the specific numbers. But they indicated the two oxygen sensors on the exhaust. Above and below the (NEW) catalytic.
Sounded like the same codes you were discussing here.

 

You’ll need to gather more information unfortunately. We can’t really identify the problem if we don’t know what the problem is.

 

No programming change available to relax the catalytic converter efficiency thresholds.

Need to know the actual codes. Lean? Rich? Sensor heater? Sensor circuit?

 

I’ll get those specifics. Thanks folks.

 

The code I’m getting is
P0420
Catalyst effieciency below threshold.
We cleared it and it was off for 10 minutes or so then came back on.
Open to any suggestions.
New catalytic and both O2sensors are new.