Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hello and thank you for your question. My name is James.
The p0430 indicates the catalyst for the left bank of the engine has reached its efficiency limit. The catalytic converter is made up of some precious metals inside it, platinum for instance, that react with exhaust gases to clean them. When these metals "wear out" they don't have the capacity to clean the exhaust anymore. The engine management computer will set a code when the catalytic converter has completely failed, however it won't pass the monitor test if the cat is functioning somewhat...it just keeps waiting for it to perform up to standard. Yours has worn to the point where the computer identified a failure at one point. Once this happens, there is no way to recondition the catalyst to reach OBDII standards again.
The short answer is that the left bank catalytic converter needs to be replaced and then the vehicle driven about 20 miles on the freeway for the monitor to clear.
I hope this has been helpful.