hi everybody!! im new to the maxima...i have a 01 SE and its throwing the p0420 p0430 and p0325 codes. whats the easieat way to rectify the catalyst codes? is the KS code related to the catalyst codes? i have new KS on the way to swap it out....however, there is no drive ability issues with it at this point nor do i live in an area where they require emission tests either...it does seem to be getting less mpg than what i feel it should get (21mpg)...maybe related to the codes? any and all replies appreciated....

 

Hi,

I can't think of a reason why the KS code would be related to the cat codes, but by now you probably have the sensor installed and can let us know if I'm wrong??
I put my own adventures with 420 and 430 codes on my 2001 GLE in this thread:
https://maxima.org/forums/5th-genera...ml#post9118973
There's no easy way to rectify the cat codes unfortunately. I can say I was tempted to look for ways to trick the downstream oxygen sensors using spark plug non-foulers - but in the end I did the job properly so I can go to Maxima Heaven one day.
Your mpg seems normal-to-good for mixed driving.

 

thanks for your reply...im lazy so i havent replaced the KS yet...my area doesnt do smog testing so im not really concerned with the cat codes....it runs really strong for 240,000 mi and it only cost me a 1000 bucks...uses almost about a qrt every couple thousand mi...so I'll just maintenance it and drive. if i drive like a gpa i can get almost 24 mpg...so im happy...was just hoping it would be closer to my civic mpg...but, with twice the engine....goodluck!! lol
will install KS and post status...

 

You may have to remove the fuel injectors to replace KS.
Nissan suggests to leave the injectors clipped Into the rail remove it all as one then turn ignition key on. See if any fuel leaks from the injectors.
the injectors are supposed to be tight.

 

The P0325 code is complaining about your knock sensor. I would ignore it, at least for a while (should the code persist, replace you Knock Sensor).

The other two codes (P0420 and P0430) are telling you that your pre-cats are worn out. They are worn out because they are (at least partially) clogged, and hindering the performance of your car.
Since you are lucky enough to live in a state where emission tests are not required to renew your licence, you have several options: a) You can gut your precats and install antifoulers to get rid of the codes, or b) You can remove the precats, install a Y-pipe, and install antifoulers to get rid of the codes, or c) You can keep them in place and keep driving. The choice is yours.

There are many posts dealing with (a) and (b) above. Just search for "gutting precats" and "Y-pipe".