Since there are SOOOO many of these posts, I want to help out because I personally have killed this code and problem free.

If you get the P0420 code check these things:
1. you may need a new reprogramming which the dealers do for around 80 bucks.
2. if that doesn't help, you may need a new catalytic converter
3. if you get this some time after installing a y-pipe, the removal of the pre-cats are causing it

SOLUTIONS (correlating to the above issues):
1. go to dealer and reprogram
2. buy a high flow cat (i got mine from Random Tech and it works beautifully)
3. but an 02 simulator from www.o2simulator.com for $30

I went through all three things and the o2 simulator FINALLY killed this code. I have a y-pipe. I replaced the cat (thinking now, i really didn't have to do this one). After research, o2 simulator took care of it.

So, P0420 people, check the above. I can't think of any other reason why you should get that code.

 

Random Tech cats have a life expectancy of bout year, after that they fall apart. OEM cat is fine, and its high flowing also. And I posted bout the P0420,P0430 fix using a simulator months and months ago. People need to start searching for answers instead of asking the same ole **** every day.

 

can you tell me what dealer did the ECU reprogram for $80 ? I'm willin to pay them to do it for $80, my dealer is trying to charge $170

 

 

Most Nissan dealers will do it for $80. I got mine done at Route 46 Nissan in Totowa, NJ.

Somebody give BlackBird a cookie. JK.

 

Same here, LI dealers are charging about $150 for an ECU reprogram. Highly considering not doing it although i have a new MAF, intake, and y-pipe. I also have po133, Heated Oxygen Sensor 1 Circuit Slow Response. Will an o2 simulator help, i dont even think i need to replace my o2. Where can i get one of these simulators?