i just replaced my O2 sensors and now a P0420 code is pending. this is catalyst system below efficiency. i got to thinking and is it possible that because i have new O2 sensors downstream and old upstream, that the upstreams are going bad.
this is my viewpoint: ok so the upstream O2 sensors are reading poorly and then the downstream are reading correctly. if the upstream sense rich and the downstream sense stoichiometric (for example) or something like that (you get the point). could this cause this code to be tripped? or did i run my O2 bad for too long and plug the precat? or the main cat?

i have no other signs of the cats being plugged, eggs smell, lost power, etc.

what the consensus?

 

p0420 needs a ECU upgrade not new o2's

http://www.nissan-techinfo.com/nissa...ima_A33_EC.asp

 

well... u got the code after u replaced the new 02 sensor? that's weird.... i am not sure i got the code too..P0420 but i got a P0430 too... dealer told me to replace new cat,not the sensors.if the sensors totally dead would store these 2 codes?i wanna know too....

 

The TSB bull****... i just got the ECU updated..and the code came back on after 30 miles driving.

 

how much should this cost at the dealer? I heard some do it for free, but my dealership is

 

the update for the tsb is covered 8yr/80k miles as mandated by the gov. the update cures the majority of P0420 but in some cases, a main cat replacement is necessary.

 

Had the P0420 at 28K, had the ECU reflashed and a new O2 sensor put in. The damn code came back at 56K. Personally reset the ECU and 3K miles later has not come back (25K more to go I guess)

 

just leave it and make sure you erase it before you get a smog check.

 

i've got this code twice on two different 2k1's, both updated by the dealer.

 

I have had my SES come up twice already, and this time, I am sure it is this code again. I am just going to leave it. it only costs me like ten minutes at autozone to erase the code with their reader. since I am not losing mileage, I dont think there would be a reason to get this checked from the dealer.

 

www.o2simulator.com will fix your P0420 code. Makes your bad cat look like new to the ECU

 

there are two white wires, one blk, and one grey. Which ones do you tap?

 

Larrio I PMed you my cell # like a week ago or so, call me around noon time or I will go outside and take a picture of how I have mine setup. I cant remember the wire colors. Year with no cats, and no CELs, my 02 sensors are just dangling there not even in the exhaust anymore- the POST cat ones, my primary ones are working just fine.

 

1 white is power, 1 white is heater, black is signal and grey is ground. you will have to test for power on the white coming off the car since neither have distinguishing marks, at least on mine they didnt. the signal wire (black) coming from the o2 is no longer connected after the simulator in installed.

 

[QUOTE=sloppymax]1 white is power, 1 white is heater, black is signal and grey is ground. you will have to test for power on the white coming off the car since neither have distinguishing marks, at least on mine they didnt. the signal wire (black) coming from the o2 is no longer connected after the simulator in installed.[/QUOTE

if i get 2 codes p0420&30..so i need to buy 2 -O2 simulators? work?

 

no, you just need the DUAL version, it has 4 wires instead of just 3. The 4th wire is the signal wire for the 2nd o2 sensor.