P2A00, 2006 Sentra, not O2 sensor, what else?

[MoneyJohn]

2006 Sentra 1.8L with ~117,000 miles on the odometer

P2A00 code showed up, and the car was running rough. The mechanic replaced the O2 sensor. (It was previously replaced at 92000/7 years ago.)

Within a day, the code is back. The mechanic did mention that it could be something different as well, but until the light, the firing changed completely. It was smoother.

The mechanic mentioned that the exhaust system, arrowed location in the picture attached, is going to break soon and it will need to be replaced.

I was wondering if a leak at this location can throw P2A00?

If that whole pipe needs a replacement, should I stick to any specific brand?

Thanks in advance.

 

[BISCUT]

I believe you may have the answer! I replaced the bank 1 O2 on my 2006 1.8 with a Bosch and 50 miles later the check engine light returned. Thought maybe the downstream O2 but it was an exhaust leak just before the downstream O2. Mechanic sleeved it and the code went away.

 

[MoneyJohn]

Mechanic sleeved it

How do you 'sleeve' it? Can you direct me to such a part. My mechanic mentioned that it warrants a replacement, and I am not in the mood of spending $600+
I am told that this region is flexible and flexes as you accelerate. If you are referring to this part, it won't flex. Would like to know the alternative.

Thanks in advance.

 

[BISCUT]

He has metal for this application he cuts and I believed tig welds to the area (really a hole). It has worked for mine for a few months and about 5k miles. No more exhaust hole sound or smell

 

[supton]

And people like to say that the downstream is only for monitoring the cat. This would imply otherwise, that downstream might be used to calibrate the upstream. At least for some engines, probably not all.

 

[MoneyJohn]

Now, the downstream sensor is shot, flex pipe is broken and the connections at both ends are rusted. Will be replacing everything.