I have close to 70K on my max and last week I pulled up P0420 code (B1 sensor). I guess it has to do with the O2 sensors and Iam in no mood to pay $400 dollars to fix them in all (4 of them) when my cat and precat are just fine. I did see in the form of the soln to fix this by fooling the ECU that the O2 output voltage is in line with a good sensor (http://www.o2simulator.com/)

Now going by this URL for a California speced car
http://maxima.theowensfamily.com/tsb/NTB02-051a.pdf

which sensor controls the fuel/air ratio and which of the others are for smog related O2 content check sensors.

I would think B1 control F/A ratio and B2 are the smog related sensors

 

I pulled this code 3 times, dealer tried the ECU re program and later it came on again, wound up being my CAT was failing, dealer changed the cat for free the other day under warranty.

 

went trough 3 o2's before it was uncovered as the problem

 

Who paid for the 02's and the labor -- u or the dealer?

 

If you pull P0420 and have under 80k miles, take your car to the dealer and tell them to fix it! If they pull P0420 with their diagnostic, you are covered under the 8yr/80k mile government mandated emissions warranty and Nissan is obligated to fix the problem.

 

yeah! go to dealer ..u are under warranty with 70k...by the way..P0420 is not oxygen sensor problem...it's the cat!!!

 

this just answered my thread. thanks

 

so if I replace the cat the code will go away... I have over 82k on my 01 SE, and what can I do... what about the catmman high flow cat...is that any good?

 

p0420 is contributed by one of the secondary o2 sensors that monitors catalyst efficiency, so theoritically its NOT the cat but the o2 sensor telling you the cat is bad.

however in MOST cases of the p0420 scenario, the ECU requires an update because the o2 triggers the ECU that the catalyst is operating out of normal engine specifications... hence triggering the code

 

I had the light go on all the time, so far I am good with the new cat, seems peppier too, the O2, I wonder if the light triggered it to run rich as my mileage is way up!

 

the rear/secondary o2s do nothing towards performance or gas mileage. They are there to monitor catalyst efficiency only

 

I took the car into the dealer after pulling P0420 again this morning at Autozone. I walked into the service dept with TSB in hand and my emissions warranty just in case. I made sure there would be no question as to whether or not they were going to try to rip me off.

While I have had the code, I have noticed a stiff decrease in mileage. So I am hoping that once Bob Moore Nissan here in Norman fixes this, my mileage will improve.

 

interesting, i've had the code on two different 01s for multiple months at a time before the tsb was done with absolute no difference in mileage. I'm always 330+ miles per tank

 

So, theoretically, it could be the secondary 02 sensors bad, or if the 02 sensors arent bad, then it could be the cat or you need a reflash, OR one of the two? (just reflash or just cat?). Seems like theres no easy answer here unless you start throwing expensive parts at it.

 

I need some more info on this ASAP if possible. My car (2002) is at the dealer right now. Went in for 30,000 mile service (bend over) and SES light was on. Got a call back from the service guy at lunch, he said the diag machine said that the 2 rear o2 sensors are failing and my manufacture warranty is up and my ext. warranty does not cover this either. Are these covered under this federal emissions warranty, or am I outta luck on this.
Any responses are greatly appreciated as I'm not looking forward to $140 each for these things.
Thanks

I'm gonna post this as a new topic also...hope no one minds

 

[QUOTE=renuen24]I need some more info on this ASAP if possible. My car (2002) is at the dealer right now. Went in for 30,000 mile service (bend over) and SES light was on. Got a call back from the service guy at lunch, he said the diag machine said that the 2 rear o2 sensors are failing and my manufacture warranty is up and my ext. warranty does not cover this either. Are these covered under this federal emissions warranty, or am I outta luck on this.
Any responses are greatly appreciated as I'm not looking forward to $140 each for these things.
Thanks


First thing I would do is get the car back and think about what needs to be done later. The code can be on till u figure out what u have to do -- these stealerships would always do this, tell u do it now OR else. Give them u middle finger

 

That is what I thought too it could very well be the O2 -- I have been seeing a lot of forum members going thro the O2 failure just around 60K miles.

My concern is I see a lot of my friends (different cars though) with lot older cars never fail smog in CA and haven't changed their cats -- I would think it is the stupid O2 sensor. That is why I wanted to know if I could feed the right voltage (good sensor's o/p) to the ECU using this hardware and not have to think about it.

I am pretty confident it is not the CAT -- I just have 70K and there are run-down cars on the street with the tags from DMV and passed smogs.

FYI, I have seen no decrease in MPG -- always the 24 MPG

 

Thanks for the response--
I wasn't going to have them put in today, I wanted time to research and see if I was covered somehow. I did find that Federal emissions warranty, it is a little vague (says 8/80,000 for cat, electronic emissions control unit and on-board diag device.) 02 sensors--where do they fall.
Thanks again.

 

When you guys are saying its the cat. Which cat are you talking about? I changed my cat. I have a Warpspeed cat on now and SES is back. I'm due for emissions and really need to get this SES light off. Could it be the pre-cat? If not then which O2 sensor should I change. Pics would help alot.

 

SES light doesn't necessarily mean its the cat. You'll have to pull the code first to check what it is

 

Talked with the service guy the code they pulled was po138, which is a code on one of the O2 sensor TSB's. I'm still very interested in this Federal emissions warranty, and tell me if I'm wrong here...but lets say I don't fix this and it causes the cat to fail, then how much talking would I have to do to get the cat AND the O2 sensors fixed under the emissions warranty???

 

I don't see how not fixing a o2 sensor would cause the cat to fail. The o2 is there to monitor the cat, now if your car and year falls under the tsb then its most likely that the ecu needs to be updated and not the cat replaced unless it becomes an reoccuring problem

 

when i got the code P0420 or 430,and i went to dealer..they told me just replace the 2 pre-cat or do a update ECM first.And i asked them might it be the bad oxygen sensors? they said no...so i just did a updated and the 420 code is not coming back yet....and i used the 02 simulator to slove the 430 now!!!

 

I have the P0420 code.

killer924007: How much did the ECM update cost you? Also how long ago did you get it done?

 

about 1 month ago.... $160 bucks man...the minimum 60 dolloars check up include yo!!!! the 0420 code hasn't come back yet,,about 1000 miles already!!! but the 0430 came back after 50 miles then i used 02 sim to shut that 0430 off....now no SES light... i shouldn't spend that money for updated.. cus i didn't know that can't slove the 430...

 

I think it is a bad ides to spend $80 for check and update of ECU -- don't understand what the stealerships have to check for when 100s of Maxima owners are coming in with a similar problem.

Anyway, I going to settle for the O2 simulator becoz I am no mood to pay $80 for an update to clear P0420 knowing very weill I need to get the simulator to shut out the P0430.!!!

 

Love, how many miles do you have on your Maxima? You should be able to get this corrected for free under warranty if you have less than 80k miles.

 

When the Service Engine soon light came on in my Max last June I went to the dealer and they found the P0420 code. They said it was a software problem and reset the ECM.....oh and they charged me $75.00 for 10 minutes work.

So when the light came on again last week (with the advice of this board...thanks) I went to Autozone and had them pull the code for free. Same P0420 code. I asked the guy to reset it....he said that he could not legally do it. So I asked how much the scanner cost.....$75.00....So I bought one and reset the thing myself. This is a good investment that I recommend.

I wonder now if the CAT is bad and the dealer told me it was a software problem (back in June) because my car was/is under 80,000 miles and he doesn't want to do the work for free. Incidentally, the car passes emission checks where I live.

Also...in another side bar to this story at a different dealership. I happened to be shopping for an '05 Max on Saturday....to my surprise the dealership I was at had Saturday service. While the salesman was getting keys for the test drive, I walked back to the service department, told the manager that I was shopping a new Max, but that my current Max had the Service Engine Soon light on & could she hook up the code reader and pull the code....not fix it whatever it was....just pull the code....a 3 minute job. She said no....NO....and that I would have to make an appointment for next week sometime. Now get this, I say, I've heard that autozone can pull the code for me do you know if this is true? She says "Yes they can but nobody except a Nissan dealer can reset the code because it takes a 'SPECIAL NISSAN' code reader to do it". What a bunch of sh*t. I fondly remembered her words as I sat in my garage and read/reset the thing in 3 minutes.....what a stupid, stupid girl.

I live 25 miles from this dealership and I have a job to attend each day......Unbelievable.....I didn't tell the salesman what happened.....I guess I should have. I know that I will never get my car serviced there. I feel bad for the salesman though, he was actually a pretty nice low pressure guy. I still might do business with him because, quite frankly, most of the Nissan dealers around here (Cincinnati/Northen KY) are pretty snake like.

This reminded me of the time that I owned a 88 Honda Accord and wanted new spark plugs put in while other work was being done, the dealer said that the plugs were $12 each. As I had not just fallen off the Turnip Truck that morning I asked what kind of plugs cost $12 each.....he said they were "Special Honda" spark plugs. So I drove home, got a socket wrench, and pulled out one of the plugs.....NGK...just about the cheapest plugs in the world.....I never went back to that dealership again....eventually they went out of business, a seemingly impossible thing to do while selling Honda's in the late 80's and early 90's. Now a much better outfit bought & runs that dealership.

Sorry for the long post. Have a good week all.

 

Which scanner did you get?

 

I'll have to look when I am home later. It is a small yellow/orange unit.

The Autozone guy got it for me.

 

The brand is Actron OBD II Pocketscan.

Model # CP9125

 

Also to note about your rant about the spark plugs above-

NGK is the preferred (many would say the ONLY) brand of spark plug to use on these vehicles, and the NGK Platinum spark plugs can typically retail $12/plug.
(not sure what you mean by the "cheapest plugs in the world" either, but I don't know all that much about NGK as a company/brand, besides they're used on tons of imports)

 

You bought it at Autozone for $75? I can't find it anywhere for that price. Lowest I found is $149.

 

Nevermind. I found it on ebay...

 

Just a little update on my problem--
Got the car back from dealer and the SES light is off...I guess it was reset???
The car has been driven probably 80-100 miles and the light has not come back on (wouldn't it come back on if the problem wasn't fixed?) For now I'm not worrying about it, if it does come back on, I may try the reset that someone had a link to for a 350z. Thanks for all the help and advice, I'll be back.
MN

 

What I meant by cheapest plugs in the world was that when I pulled the plugs from that Honda 4-cyl and took the part # to Autozone, they turned out to be the base NGK $1.49 (at the time) each plug.

I like NGK and continued to use them for many years.

 

I just ordered the hardware to bluff the ECU (simulator) for $30 and would be disengaging the signal output for both B2 sensors fed back to ECU.

 

I installed the O2 simulator on both my rear sensors. It works like a gem and don't get P0420 codes (even fixed the P0430 with the dual o/p simulator).

Interestingly, the o/p of the simlr is 325-630mv which is around normal operating voltages for a good O2 sensor -- but now it thros P0171 (Oxygen Sensor System Too Lean Fault Bank A) code, I rechecked the voltages and it continues to be from 320mV--630mV. I don't understand why the ECU picked up a voltage less than 100mV to trigger this code.... Any thoughts!!!

 

I've had the p0420 code twice. The first time it went on, the dealer told me they had to reprogram the ecu. The second time about 4 months later, it came on again. I simply had autozone clear the code and it never came back again after that. I think it was just a fluke.

 

i had this code too... i needed a smog test and thought i wouldn't pass, the day before i disconnected my battery to do something and when i plugged it back on the light was gone... so luckily this helped me pass the visual inspection of the smog test... after the test the results said i passed perfectly.. and i never fixed the 420 problem...