[Gogeta19]

Any recommendation I'm in lowell and prefer some where near by got a P0430 which I believe is the catalytic converter is going with 204K. Thank in advance

[b92]

Have you noticed any other changes in how the car is driving? Exhaust sound, engine stumbling, decreased acceleration, increased emissions, etc.

If you're only getting the P0430 code (and not P0420) then it could very likely be just a faulty post-cat o2 sensor. Your code is for bank 2, so this would be the exhaust coming from cylinders 4-6. One way to test this would be to clear the codes and then switch around your rear o2 sensors - if the P0430 code persists then it's definitely the o2, but if you get the P0420 code then it's the cat.

[Gogeta19]

I would say decreased in accelearation and probably gas mileage as well.
The two sensor in the rear is compatible by switching over see if the the sensor was bad it would throw a different code to the other bank?

Here a live clip of the data I did with Protool.

[b92]

By switching the o2 sensors and keeping the cats as the constant, you can determine if your issue is with the o2 sensor or the cat:

Current:
Bank1 post-cat o2 connected to Bank1 exhaust - no code (good sensor, good cat)
Bank2 post-cat o2 connected to Bank2 exhaust - P0430 code (bad sensor or bad cat)

After switching the o2s, you will run into either of these two scenarios:
Bank2 post-cat o2 connected to Bank1 exhaust - no code (good sensor, good cat)
Bank1 post-cat o2 connected to Bank2 exhaust - P0420 code (good sensor, bad cat)

Bank2 post-cat o2 connected to Bank1 exhaust - P0430 code (bad sensor, good cat)
Bank1 post-cat o2 connected to Bank2 exhaust - no code (good sensor, good cat)

Then there's also the possibility of a bad cat fouling the o2 sensor, requiring both to be replaced. This would throw both P0420 & P0430 codes after switching the o2 sensors:
Bank2 post-cat o2 connected to Bank1 exhaust - P0430 code (bad sensor, good cat)
Bank1 post-cat o2 connected to Bank2 exhaust - P0420 code (good sensor, bad cat)

I'm not sure what the read outs should be for the diagnostic values, however I'm not sure if that can help determine whether it's the o2 sensor or that cat. The fact that you are getting a read form the sensor might point to the a faulty cat, but I don't know enough about the system to draw any conclusions.

[Gogeta19]

I'm only swapping the two post rear sensor right?
Bank 2 sensor 2 sensor (original) will be at bank 1 sensor 2 location.
Bank 1 sensor 2 sensor (original) will be at bank 2 sensor 2 location correct?
If bank 2 sensor 2 does not throw code after swapping mean the cat and sensor is good?
If bank 1 sensor 2 throw code P0420 (bad sensor, good cat since original there was no code before the swap)

Just want to make sure before attempting this troubleshoot tomorrow morning.

[b92]

Originally Posted by Gogeta19

I'm only swapping the two post rear sensor right?
Bank 2 sensor 2 sensor (original) will be at bank 1 sensor 2 location.
Bank 1 sensor 2 sensor (original) will be at bank 2 sensor 2 location correct?
If bank 2 sensor 2 does not throw code after swapping mean the cat and sensor is good?
If bank 1 sensor 2 throw code P0420 (good sensor, bad cat)
*So the P0430 doesn't follow to the bank 1 sensor 2? Or it just different code but meaning the same thing as the cat is bad?
Just want to make sure before attempting this troubleshoot tomorrow morning.

Yes, only swapping the rear o2s. I'm not sure how difficult this will be on the N52 exhaust but it certainly isn't an easy task on the N54 exhaust.

The two codes are tied to what the o2 sensors are reading, not the cats. So if the P0430 code follows bank 2 sensor 2 when installed on the bank 1 exhaust, then we know that sensor is bad. If the code doesn't follow and you get a P0420 code instead, then that means both the bank 1 and bank 2 sensors read that the bank 2 cat is bad.

[dpaul]

Probably a little after the fact but:

Perhaps you can just swap the connectors - if the code changes from P430 to P420 then the rear sensor is the problem, if not, it could be the cat.

I don't know about the N52 engine but swapping the connectors is far, far, far easier on an N54 than swapping the sensors themselves