New Engine and 2 Catalytic Converters Needed for 04 Maxima?

code p 0431 refers to warm up catalytic converter, bank 2--efficiency below threshold === causes ---cat converter---wiring---HO2S sensor 2
it should be a v6 engine as it has 2 banks , bank 2 is the one closest to the grill.
there should be 2 cat converters ( one for each bank)
from the suggested causes , I suspect that the HO2S sensor is not performing properly and is not providing the correct mixture to the cat converter to make it operate properly
if you bump the cat converter with the hand and it rattles , it will need replacing and autozone would be right
However I am always of the opinion that you should seek other advice from an accredited exhaust specialist shop and get a quote as cat converters are not cheap

When replacing your converters you can eleminate the second converter, shops in different states have different rules that may prevent them from losing the 2nd converter but you as an end user can but an aftermarket converter that will fit your car and install it yourself. This will require a sawzall or a good hacksaw to remove the old units so as to leave enough pipe coming down from the exhaust manifolds for the new converter to clamp on. Once the new converters are installed any muffler shop can hook up the rest of your system.

Hello Anonymous,

Were I you... (my best guess)
I would be looking for a BLOCKED EXHAUST...

(in my opinion)
probably the number one REASON AUTOZONE
sells so many (pointless) OXYGEN SENSORS...

Those new OXYGEN SENSORS Pretty much
complain as well as the old ones did...

The logical equivalent of buying a NEW
THERMOMETER... because you have a fever.

Check out the whole system costs on AMAZON,
eBay & rockauto... BEFORE waltzing into any
exhaust shop...

Catalog:
http://www.rockauto.com/en/catalog/nissan,1999,maxima,3.0l+v6,1356780,exhaust+&+emission

Catalytic converters ($$) C.A.R.B. Compliant available
1999 NISSAN MAXIMA 3 0L V6 Catalytic Converter RockAuto

C.A.R.B. specific details (2 day ship'n, About $280)
More Information for DAVICO 169750

Exhaust shop should be able to test...
(OXYGEN SENSORS... save your $$$$ = nah)
Hope this helps

Carnac the Magnificent

Your catalytic converters may be plugged. They have had problems out of the converters on the G6s. Probably have to take it to a mechanic, but im going to forewarn you, a catalytic converter for a G6 is around $1,000.00 each, and if its a V6 theres two converters. What I did was went on ebay and I found 2 brand new converters, one was $227.00 and the other $238.00 free shipping on that one, and they also have remanufactures converters too.

The used engine that you bought was previously damaged by the disintegrating cats that were on the car that it came from and because it was burning oil badly when you installed the new cats, it ruined the new cats with the oil that was coming out of it. You'll need a re-manufactured engine, not a used one, they are all bad, and new cats again. Bad news I know. but likely the problem.

The main ground wire brakes where it connects to the transmission. look under the battery carridge

A 2003 vehicle probably did not need a new converter. Cat converters have to be run for years before they clog up. Depending on what kind of vehicle this is, you may have a post catalytic oxygen sensor problem. Also, depending on the vehicle, you can not just replace the converter with any old converter. Many vehicles require an OEM replacement converter in order for the sensors to work properly and these are expensive. Kansas City Converters (available online) sells replacement converters for a fraction of the price that will work with post catalytic sensors and not cause the check engine light to come on.

P1320 = Msnufacturer control ignition system or misfire

Note: Misfires are destructive to catalytic converters
DO NOT IGNORE NEEDED REPAIRS

HI
yes there is two catalytic converters ???
one for any exhaust pipe bank (left & right) (bank 1 & bank 2 )
if you change the bank 1 ?? may be you need to change the bank 2 today?????
but not to change the same bank two time ???????

ask for more information
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