OBD Code: P0430 2001 Nissan Maxima

[Riley]

Same 2001 Maxima as the fuel gauge (190,000 miles). This involves the Check Engine light…

About a year and a half ago (approximately 160,000 miles), the CEL came on and threw two codes: one was indicating a “lean” condition (turns out a bad MAF sensor, had to replace with OEM sensor. For those with Nissans, MAF sensors are impossible to clean and have work again correctly, per the parts guy I talked to AND mechanic who helped diagnose the issue… just as an FYI) and the other was a P0430 (Catalyst efficiency threshold, Bank 2). After my mechanic diagnosed the issue for me, he said he is 99% confident the issue is the Bank 2 pre-cat which is bad and needs replacing (this would be underneath the header closest to the front of the car). The engine is a 3.0 V6, model VQ30DE.

I have 3 questions regarding this code:
1. I have noticed no performance issues with the car. The engine still red lines with no problem (something my mechanic showed me indicating there is very little back pressure from the Cat… it’s just dirty, I guess). Is this an issue I still need to be concerned about?

2. If I do need to replace the CAT, I will almost certainly go with an aftermarket part. The OEM part quoted was nearly $900 installed and I cannot afford to put 1/4 the value of the car in a single repair unless it is completely unavoidable. The brand quoted to me was Catco, which, installed, would cost about $250.

3. For my own curiosity and the fact I came across a single post in another forum that said this… could this possibly be that my engine simply needs new spark plugs? I have not replaced the plugs in appx. 80,000 miles… could this cause this code to be thrown?

*It is worth mentioning that I have heard and read (even on this forum) that aftermarket catalytic converters may not necessarily cure the code due to the difference in tolerances (and quality) between OEM and aftermarket parts. Has anyone had any experience with this code? I have been told (and after a brief google search, have been able to confirm) that this is a VERY common on this vintage Maxima. Any advice?

Topic

[college man]

If you have no exhaust leaks at the cat. The the cat has lost
its efficiency and will need replacement. with a scanner and the
car at operating temp. check the the o2 voltage signal to the o2 sensors.
The front and rear will be close to the same signal voltage. which sets
the code. If you do use an aftermarket cat. The code may stay or come back.
Also find out why the cat got destroyed. possible causes are running rich,
misfires.

[Author]

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