P0420 code
 

Hey all,

no search capability (will donate in Jan, cash short right now).

I got an SES light and pulled a P0420 code. Think its my o2 sensors, correct?

I should be able to drive as the only issue is emissions, is that true?

thanks,

das

The car will run fine. Drove mine for 4 months with the 0420 code.

You'll need to take it to the dealer for a ECU reflash.

Im bringing mine in this weekend for the same code. According to the nissan manual, its a catalyst issue. Should be under warranty for 80k.

good to know, I didn't think it had anything to do with the ECU.

code reads: catalyst efficiency below threshold. thought it might be the oxygen sensors.

let me know how it goes and if they charged ya...

d

Just got back. They wanted to charge me for the ECU update, until i informed them that it was under warranty. I had to pay the diagnostic since I had another bad coil. Guess its time to replace them all. Wife took car so Im not sure how its driving yet.

I have the P0420 code, also. I have a Hayes repair manual that explains how to test coils with an OHM meter. Has anyone tested a coil this way? Is it an accurate testing method?

I went to Jeff's today (MaximumTuning.net) since I had my SES light on and off for about 2 weeks and he pulled the same P0420 code that you guys are talking about - he said it read- "catalyst efficiency below threshold or low" Jeff then mentioned that maybe the o2 sensors may need replacing (as per Nissan) but would look into the code and let me know 2moro. But now I am reading this thread and see an ECU flash is in order.

Jeff K- why does this code occur and why does it need an ECU reflash?

ktm250rider- my Max is at 49,200 miles so I am assuming that I can bring it in for the ECU update at no charge? Is this correct? Also it sounds that are cars are twins in that I believe I have a bad coil also. Can you tell me what code was indicated for your bad coil(s)?

Jeff at MaximumTuning pulled another code- 1320 but the reader did NOT give an expalanation to the code. Can anyone tell me what that code means?

Thanks,

Angelo

Code P0420 - 'catalytic converter too stoned to function properly'
I've had that code for a while... if I could just figure out where the crap my catalyst is getting pot from, I'd be able to make it go away.
Try letting your car sit with the negative terminal disconnected over night - I just recently did that and 400 miles later, no code. Sometimes the code goes away on its own, but returns 50 miles later. Maybe because it's now cold outside, dunno.

ive been told the 0420 is a precat that has gone bad. its covered under a 8yr./80k federal emission warranty. the replacement of the pre cat is done along with a reflash of the ecu that has been mentioned earlier. they may try and charge for the reflash but it should be covered under the emissions warranty.

Sterling,
I belive i got a P0302 which is a cylinder #2 misfire. They may charge you for the diagnostic but the reflash is covered under warranty. (ECU and Cat are covered 8/80). Once they were aware of it, they covered it. Even though I knew the code (autozone) they still bilked me for the diagnostic since I had the coil error as well.

well, I finally took my max in today to fix the damn code. all they had to do was update (reflash) my ECU and I was golden. all covered under warranty!

sweeeett.....

das

P0302, P1320 are coils. You have to get them all replaced. (happened to me)

p0420 just requires a ECU reflash. Both my 5th gens have got it, both at around 20-23k miles

both performed under warranty, free of charge. The tsb is on the nissanusa.com main site.

My nissan dealer blows, every time ive mentioned it they say no such TSB exsists :banghead:

lemme see if i can find a copy of my service write up and i'll copy it and send it to you.

then you can shove that in their face

Cant wait :thumbsup:

So it isn't the main cat? If not can an aftermarket y-pipe cause this problem? How exactly is it fixed?

No its the pre-cats. I forget what the exact words were on the scanner but it was something like pre-cat efficiency is below normal levels or something. It has nothing to do with the main cat. I dont know if the codes meaning differs from Cali & Fed specs though :gotme:

I was wondering if the y-pipe causes this as well, but the weird this is since mine is a cali-spec I was only able to use half the y-pipe & had to leave the front half of the y-pipe alone. I drove like that (one pre-cat gone, one still there) for 6-8 weeks & no SES light. Then I said screw it, I wast the whole thing, thats when I gutted the front pre-cat. Techincally I have use of the whole y-pipe now, rather then just half BUT my SES light went on about 50 miles after I gutted it. Took about 3-5 drive cycles to go on but it did. I always thought it was due to my tinkering that the SES went on.

I kinda still do to be honest but Larry is saying otherwise. This is been discussed be4 several times, but I still dont know which way tp approach this. Every time ive sent a max to the "stealership" they told them no such TSB existed, including mine. Even if they do admit it exists, im thinking they are going to place blame on the y-pipe.

So if one precat is left on a cali spec and it is the problem does it actually need to be replaced by the dealer? Has anyone had this done before?

Maybe :gotme: Even it doesnt need to be replaced, the dealer will replace it & charge you for it. How are you going to prove it really was working? Either that or they are gonna say its the o2's & change them all :rolleyes:

I forget the code that Jeff (MaximumTuning) pulled but it stated "pending misfire cylinder #4" or something like that. Going to order just 1 coil for now since $$ is tight from the holidays and since I just ordered a Cattman y-pipe... :thumbsup:

After I install the new coil and before I install the y-pipe, I will go to get the ECU updated.

The P1320 code, I found out from another thread is- P1320 ignition signal primary circuit fault- which points to ignition coil(s) also. I will see if that code persists after I replace the one faulty coil. If it does then I will start replacing the remaining 5 coils......
Gonna do some more searching... now that I can :deezo:

They changed my O2 and it didn't go away. they reset my ecu, reprogrammed it... Still SES.. Then they put in a new ECU installed the latest software. Went away for about 50miles. Then back again... Now they are saying it is my cattman y-pipe. I took it off it is going back in lets see what happens.

I know of a few local max's that are 100% stock & still pull the code Po420. I cant prove it with facts, but I still kinda doubt its the y-pipe. If it was, mine would have gone off as soon as I put the y-pipe on. The SES didnt go on til I gutted the cat, I think it might just be a conicidence but who knows.

i've gotten that code twice in two different 5th gens STOCK

Im not surprised, its just with mine it happened about 50miles after I gutted it so I have/had a good reason to belive it was due to that. Let me know when you can get your hands on the service write up. I really want to go to the dealer sometime next week and see what they have to say about it...again.