Code the code, P0430. I read up some stuff here on P0420, so is this the same problem just related to the front bank?

The flex part of my y-pipe is broke, so I am going to replace it with new (used) OEm y-pipe. I hope the cause of this is leak in exhause system..

Any suggestions/thoughts..
Thanks

 

Diagnostic Trouble Codes (DTC) P0430 and P0431 indicate that bank 2 catalyst system efficiency is below the acceptable threshold

If you take a look at http://www.v8sho.com/SHO/P430.htm (might be for an SHO but the diagnosis is correct), it says "Note: If a catalyst is in series with a leaking exhaust system, it can fail the Catalyst Efficiency Monitor test."

So if you fix your exhaust system and you should be .
Jack

 

the nissan fsm states a much more complex diagnosis with the consult-II. However the exhaust leaks COULD BE one of the symptoms to your problem.

somehow I doubt it. If you have a cali spec 2000, that secondary o2 sensor is monitoring the precat in your front manifold, not the catalytic converter. Meaning that there is one primary o2 (blue harness) at the top of your front manifold right after the exhaust ports in the head and then one secondary o2 (red harness) right after the precat at the bottom of the manifold right before it converges to the straight section on the y-pipe.

The P0430 is monitoring the efficiency of the cat by comparing the exhaust stream after it passes through that precat and comparing it to readings from the primary one.

 

www.o2simulator.com will fix this problem for sure