any nissan mechanics out there

[blasterfreek30]

my 01 pathfinder has failed emissions, so got the code reader and it said p0420 and p0430 which is telling me if have 2 bad catalytic converters, there is also other sites that say it needs to be reporgrammed, or bad 02 sensors...i really dont have the dough to buy 2 new cats and what are the chances that 2 of them went bad at the same time...and id be abit pissed if i did buy them and it wasnt the problem....anyone have this issue:-/:-/

thanx guys

 

[mike2225]

if the o2 sensors failed the ecu will guess at fuel and making it rich. rich mixture will kill cats quickly and plug them up. i have a hardbody and im very familiar with the nissan 3.0 and 3.3's. check out this site nissanforums.com and infamousnissan.com

 

[OConnor Racing]

When it comes to cars and trucks, I'm no technician but I can offer this. I had a cat go bad once and this is what it did. The engine had no power and the sound of the exhaust was very quiet. The exhaust gas coming out of the pipe was very hot. If you looked at the cat at night, you could see it glowing red.

 

[blasterfreek30]

yea i dont think that the cats are bad...there is no performance loss and it does smell at all....usaully u can smell sulfur real bad when a cat is bad

 

[mike2225]

what were all your emission readings? hc's?

 

[scotj77]

I would replace the O2 sensor and see what happens. i faild emitions once and I just took a wild guess and replace it and it fixed the problem. the cat's are probably fine

 

[sicivicdude]

The catalytic converters are "checked" all the time by a set of oxygen sensors. Pre cat also acts as the stoich check for the engine parameters making sure that the engine is running properly. The post cat O2 sensor runs continuously making sure that there is nothing in the stream after it goes through the catalytic converter. If either go bad it will cause the computer to think that something is wrong with the cats.

I would start with one post cat O2 sensor and see if that clears up one of your codes.

 

[mike2225]

yeppers! those suckers arent cheap either. and with 4 total... :-( you hope only one is bad.

 

[MINIGfather]

not sure what engine is in yours but i had a maxima w/ the 3.0 V6. Im pretty sure thats the same code mine had and it was an O2 sensor. Prob your cheapest part....

 

[super noober]

x5 on the o2 sensor man, good luck I:I

 

[blasterfreek30]

thanx alot guys....ive been looking and alot peeps say the same thing about the bad o2 sensor...1 more thing is its says that they are (bank 1 and bank2)....are they the post cat sensors?

 

[super noober]

thanx alot guys....ive been looking and alot peeps say the same thing about the bad o2 sensor...1 more thing is its says that they are (bank 1 and bank2)....are they the post cat sensors?

i had a escape once and when it said that it was referring to the sides of the motor because there was a O2/cat attached to each exhaust manifold on both sides of the engine.

 

[blasterfreek30]

ok so bank 1 could be the left side and bank 2 could be the right side then??

 

[super noober]

ok so bank 1 could be the left side and bank 2 could be the right side then??

could be lol, google that sh*t hahaha I:I

 

[Blasterdude27]

Man I though my trooper was bad with two 02 sensors! 4 would suck!

 

[sheeblast]

p0420 is an O2 sensor code.
known nissan code and problem.

 

[245stroker]

No emmission checks here! My s-10 has the same issue. One of the o2 sensors is bad but the mechanic told me if it doesn't run any different, don't worry about it.

 

[brandoz28]

bank 1 is driver side, bank 2 is passenger side, sensor one is pre cat, sensor 2 is post cat

 

[blasterfreek30]

awesome, thanx alot guys, i new yall would help

 

[Dude]

Post o2 sensors do nothing but check to make sure the front 02's are correcting. They will do nothing for emission. The pre o2's are what the ecu's see's and adjusters its fuel curve and timing curve with. It has been this way since obd and carries threw to obd2. Hence the standard.

You need to post your results so i can guide you threw why you failed. If you want to fool the sniffer assuming its just sniffer denatured alky is the key. I have been a tech at ford for over ten years.

I also have my vw and nistune cert as well.
P0420 Error Code: Catalyst System Efficiency Below Threshold (Bank 1)

Bank 1 is always driver side. Again obd is a standard for all vehicles all codes are the same from obd threw present.

Measure the voltage on both banks and all 4 sensors and report back here. I can tell you if there working and in range.

Find someone with a aldl cable and i can send you nistune to rip the prom data from the ecm and i can go from there and find out what the ecu is doing and why.

Check these things. You want fool proof take your car in for a estimate somewhere thaqt is free get it diagnosed and change on your own. At are dealership we do this for free. Call around it behooves you to do so.