P0430? What to do?

[blue62]

Originally Posted by staircasesurfer

Black_Boxster did you ever resolve this issue? What were your findings?

I am in similar situation, Occasionally popping CEL for a P0430. Hoping it is not the cat. Planning to check o2 voltage with code reader to compare pre and post cat 02 voltage on both banks.

I may just need to give it a good spirited drive or two, too much commuting.

Exhaust leaks at or before the post cat O2 sensor can also cause the P0430 code.
Pin holes at the O2 sensor bung weld can cause the code, and can be very hard to detect.
Cats are actually designed to last the lifetime of the car. So if you have had no other problems with the car that could affect Cat health, you always use good fuel, your fuel trims are not constantly rich or lean. Your AOS is not or has never been faulty. Then I would look for other causes for the code.
Anything that could cause excess oxygen into the exhaust or a fault with the O2 sensor its self.

What year is the car and how many miles??

[staircasesurfer]

Originally Posted by blue62

. Your AOS is not or has never been faulty.

What year is the car and how many miles??

It is a 2001 S with 125k, AOS replaced at 58k. Possibly it is failing again and fouled the cat. Not sure that would only affect one bank and not the other. Checked o2 voltage and bank 2 sensors are chasing each other, post cat voltage is wave between .15-.75v.
Bank one looks ok, post cat voltage pretty flat at about .68-.72v.

[blue62]

Originally Posted by staircasesurfer

It is a 2001 S with 125k, AOS replaced at 58k. Possibly it is failing again and fouled the cat. Not sure that would only affect one bank and not the other. Checked o2 voltage and bank 2 sensors are chasing each other, post cat voltage is wave between .15-.75v.
Bank one looks ok, post cat voltage pretty flat at about .68-.72v.

This P0430 code can be very difficult to diagnose properly.
It could be the cat as JFP stated, but they are an expensive part to just replace without knowing for sure that it is the problem.

A few things that can cause the code other then a bad cat are.
Exhaust leaks
Leaking fuel injectors
Vacuum leaks
Bad O2 sensor

You most likely don't have a vacuum leak issue because your Bank one O2 sensors seem ok. A vacuum leak would affect both banks.

So I would look very closely at the exhaust system on bank 2 for any leaks.
It just takes a pinhole size leak to cause this code so they can be very hard to find.
Check the exhaust clamps as well.

You could swap the post O2 sensors from side to side and see if the code follows the sensor or stays on bank 2. That is a way to prove the sensor good or bad.

You can use a infrared temp gun and check the temp of the cat to see if it comes up to operating temp to function properly.
This last test is a little tricky to do correctly.
Lots of Youtube examples but you have to watch the right ones to get correct info.

I will see if I can find one or two correct ones to watch and post a link for you later today.

When you check the exhaust also look at the condition of the cat, any dents or things of that nature. Strike it a few times with a rubber hammer to see if anything is loose inside.

Any damage like that kills them.

Have you had any other codes or any other issues currently or in the recent past?
Does it seem to run correctly and strong?
Start easily?