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Hello my friends,

I am trying to diagnose the infamous P0430 (Catalytic converter system, bank 2 - efficiency below threshold). From what I am reading, it can be one of three things:
1) Catalytic COnverter not doing its job. It can be cleaned up in various ways I guess or replaced which will cost me lots of $$
2) leak in the exhaiust system somewhere
3) O2 sensor may need cleaning or replaced

If I were to start deciphering this issue, should I start with the O2 sensor in Bank 2? If so, I would like to know where it is located on my 08 Taurus. Pictures would be great. ( I tried to look online and no luck)

Also, has anyone tried the SeaFoam trick where you poor it down the sensor opening and letting it run through the system?

I am trying to fix this for my daughter who is at college where there are no mechanics nearby. So any help would be truly appreciated.

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The problem is NOT the bank 2 (radiator side) post cat O2 sensor. A failed post cat sensor will never set a 430 code. 420/430 codes indicate a failed cat 90+% of the time. Sometimes replacing the pre cat sensor will fix the issue, but often not. Try a "MIL Eliminator" (they look like spark plug antifoluers from years gone by) that move the post cat O2 sensor out an inch or so from the pipe. Get them from Ebay or Amazon for around $20. They work, but if you have a visual inspection it will flunk if the inspector sees the MIL eliminator.

IMO those "cat cleaners" found at the local parts store, washing the cat in various chemicals, etc rarely, if ever works.

Several years ago, daughter 13 Limited threw a 430. Car was still under warranty. Told her to tell the dealer mechanic the bank 2 cat was bad and to replace it. Mechanic replaced the post cat sensor and sent her on her way. I told her the CEL would be back on within a week. Guess who was right. 2 days later CEL on again with 430 code. She took it back to the morons at the dealer who replaced the bank 2 cat. Problem solved.
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