Hi everyone,

I failed a smog on P2A00 for my 155k 2009 sedan. I consulted a shop who suspiciously quickly decided it was a cracked cat and suggested replacing both sensors and welding the cat. I had a bad feeling about this so brought it for a free diagnosis at a muffler shop who lifted it and said they did not see any obvious problems with the exhaust and no cracks in the cat. I found a reputable shop to replace the upstream passenger O2 sensor with Denso OEM but the code returned. At the time, I requested they replace the driver side as well but they declined to do it when they could not get it unscrewed from the exhaust manifold citing fear for damaging the threads. They also declined to remove the exhaust to do the job due to rust and fear for damage to the bolts etc. When P2A00 returned the shop told me to get Infitiniti to diagnose it because they had done what they could. Inifiniti charged a ton for a "failed smog diagnosis" and did not give me a satisfying answer.

Their diagnostics showed the following:

"Air Fuel Sensor: Pulled p2a00 air fuel circ. View live data and found it reading .200v higher than bank
2. Unable to tell if factory sensor is used, appears aftermarket. Rec both sensor at this time. driver side
labor 2.4 passenger is 3.3 plus to set srt/s"

They want $2273.00 to replace the sensors due to the labor of removing the exhaust manifold. I am also being told that this might not fix the problem because there might be a hairline fracture in the driver side sensor threading that could have been caused by the other shop trying to remove it (which I highly doubt because of how hesitant they were to mess with it). To be honest, that sounds like BS and a way of justifying their eventual suggestion of replacing the whole manifold.

My garage reviewed the report and stated they weren't comfortable removing the manifold. They even recommended seeing if a muffler shop would weld a new bung for a new sensor onto the manifold but wasn't sure of the legality there.

I feel like I am looking at a potential cost of thousands of dollars that might mean selling the car is a reasonable consideration. Has anyone else dealt with a similar problem? I thought Infiniti of all places would be able to give me a solid answer vs. "we can do this for thousands but it might not help".

Anyway, sorry for the long story. Hopefully someone out there has some suggestions before I have to take a plunge.

Thanks for your help!

 

Move to or register the car in a non smog state lol

They couldn't smoke test it for cracks/leaks?
Also never heard of an exhaust shop afraid to bust out the old torches to get something apart.
Not trying to be rude, but are you presenting yourself as a PIA customer? I turn away easy jobs if i think the owner is going to be a hassle.

Anyway,
You could replace the "suspected aftermarket" sensor yourself, for penny's on the dollar.
then the dealer wouldn't have that to whine about at least.
Might want to invest in a can of penetrating oil, start spraying all the exhaust bolts on the daily. Multiple soakings and heat cycles will help all those fasteners stuff come apart. There will be smoke as it burns off though.

You could look at this situation as an excuse to buy those high flow cats and CARB approved cat back exhaust your car has been dreaming about.
But then you'll have to find a tuner to get it tuned.
But but then the tuner can turn off any annoying trouble codes if need be.
Might even cost less than trying to keep it all stock
Good luck!

 

try this. I've come across several people who it helped with that code.