A while ago I got SES light and being me I just reset the ECU hoping it would go away, but about 1000 miles later I got the light again. So I went to Autozone and pulled the code. It was P0420 (Catalyst System Efficiency Below Threshold). And I got 2 of these - 2 of the same code.

Now I know this could either be catalytic converter or o2 sensors. Is there a way to know for sure? I hope it's just bad o2 sensors...

 

bad news, it is not the o2. good news, the repair is covered under an 8yr/80k warranty. this is good new only if you have under 80k miles. the dealer should reflash the ecu at no charge and you should be set. some have had to replace their main cat due to the flash not curing it but that was also covered under that federally mandated emissions warranty. i have a link at home that describes the tsb (technical service bulletin) so you can print it out and bring it in to the dealer. ill post it up when i get home unless someone has quicker access to it.

 

Thanks a lot sloppymax! That's actually good news because I have about 45k miles on the car.

If anybody can direct me to that TSB that would be great!

 

Is it this one?
http://maxima.theowensfamily.com/tsb/NTB00-070a.pdf

 

HKMAX: How did you reset the ECU?? Did you just disconnect battery for a couple of minutes?

Thanks.

 

You have to disconnect for good 3 hours. A few mins won't do it.

 

Most likely, it is just a fault code which it is 90% of the time. Take it to the dealer and have the ECU reflashed. I had the same thing and that cleared it all up.

 

Hey my car has that same code, how do I know if I can get it fixed for free as well? It went off cuz I used to have a test pipe on my car..

 

I Just noticed this post (posted the Transmission/Engine problem) Does this Bulletin apply to Infiniti's as well because my girlfriend just paid $170 for this...I will not be happy when I call them up tomorrow if this is the case

Thanks again,

Jason