if i unplug the rear oxygen sensors( red and white wire) for my 00 max( cali spec) ..what ECU codes will it show??? u guys know?

 

try it and find out

 

P0140 & P0160 should appear. this code is O2 sensor no activity, one for each bank. this will cause your ECU to go into closed loop mode and you run the chance of plugging your precats. if you get a y-pipe you will eliminate the precats altogether.

why would you want to do this? disabling your emmisions system in order to gain a few HP is rediculous. sorry just my opinion.

 

heh...just i got a P0420 & P0430 problem..i am planning to replace the 02 sensors if my sensors are dead...won't help right?

 

420 & 430 are catalyst inefficiecy. this probably means your precats are already plugged or you need an ECU upgrade.

 

i am already got a ECU upgrade already...paid 100& 60 minimum check engine..the SES light came back on after 30 miles..damn...a waste.. any suggestion?? replace 02 sensors or y-pipe? cus i don't wanna pay 900 for the 2 stock pre-cats from dealer for my max(cali spec).

 

id say get a y-pipe IF the precats are bad. O2 sensors probably wont help because there is no code for them, so seemingly they are fine.

 

but he's got a cali spec, a y pipe won't eliminate both precats, only one. So the only way other than factory precats, is headers with o2 sensor relocation or add custom precats or at least one custom precat and y pipe...

 

yeah!!! after i got my ECM updated and the code came back but only 1 left p0430..p0420 gone... maybe i will get the front part of pre-cat from the dealer cost $423.00...what u think?

 

is po430 the front precat (radiator side) or firewall side. If it's the firewall side, you're in luck, a y pipe eliminates the "firewall side" precat. But if it's the front precat, then you'll probably have to get one from Nissan, try DAVE Burnett for a price. Or again, get headers and modify the location of the downstream O2 sensors. On the Cali spec cars, only one precat is eliminated because the front precat is used to fool the ecm into thinking you still have two precats. The "firewall" side downstream O2 sensor will read exhaust from the "radiator" side if you get a y pipe.

 

P0430 is bank 2 which is radiator side.

 

better check this thread if you got codes.....

http://forums.maxima.org/showthread.php?t=359882