My "Service Engine Light Soon" came on a couple of weeks ago in my 2001 SE 5spd. I took it to my trusted mechanic and they said that the code was "PO420 - Catalytic Effeciency Below Threshold". They told me that it is sometimes a fluke and reset the light and said that if it came back on that I should take it to a dealership since the converter is covered under an 8yr/80K mile warranty.

So, the light came on yesterday when I was driving kinda hard and I've set up an appointment for Monday at the dealership.

I'm definitely not excited about taking it to the dealership, but at the same time I want the problem fixed (hopefully for free), so I guess I'm stuck.

I saw someone posting about the exact same issue on another messaging system and was wondering if anyone else has had similar problems and how it was resolved? I don't know if it could be related, but the car has a K&N Air Filter in it and I have no idea when it was cleaned last and therefore I've decided to replace it with an Amsoil Air Filter since that's what I've used in other cars and I already have the Air Filter Oil that goes with it, etc. If the air filter is in bad shape, could that be the problem? I personally think the car runs a little rough, but both the dealership and my mechanic don't think it is bad enough to worry about.

I just got this car two weeks ( ) ago and I'm a little worried...Overall in the long run I anticipate having good luck with the car, but we're off to a bumpy start to say the least.

Thanks,
Mike

PS:
Anyone have any suggestions on how to get a OBDII Interface for my laptop cheap? I'd love to be able to get some software on my laptop (Win2k) so I could monitor the car's operations, view and reset codes, etc, but it's not something I can really put very much money into at this point...

 

There have been problems with o2 sensors going bad. I'm not saying it's not a bad converter but chances are it's a bad o2. Also a bad sensor can shorten the life of the converter.

Most obd2 systems out there are around $100-200. Most of the cost is for the connecter and cables.

Welcome to the org.

 

I have 34K miles on my 2001. Are the o2 sensors covered under warranty at this point? I'd prefer to have my regular mechanic do all the non-warranty work...

 

Take it to the dealer and get if fixed for free. i took mine to the dealer twice, once for reprogramming and second time to replace my cat. Either way it was free..

 

Cool, I found a TSB for the error code that I'm getting:
----------------------------------
Component Description:
INTERIOR SYSTEMS:INSTRUMENT PANEL:GAUGE:INDICATOR
NHTSA Number: 619999
Bulletin Number: NTB00070A
Bulletin Date: MAR 2001

Vehicle: 2001 Nissan Maxima
Summary:
SOME VEHICLES MAY EXHIBIT A MALFUNCTION INDICATOR LAMP ON WITH DIAGNOSTIC TROUBLE CODE P0420 (THREE WAY CATALYST FUNCTION) STORED IN THE ECM. *TT
-----------------------------------

I am taking it in to the dealer on Monday to have them look at it. However, I'd like them to investigate another problem though I don't see a TSB for it for my car.

What's happening is that when the car is rolling along in 1st or 2nd gear at a slow speed I either have to ride the clutch to keep the car from jumping or I have to be VERY timid on the throttle. It's pretty ridiculous, really. I've seen others post about an issue like this, but don't see any TSBs describing the problem. Anyone have any ideas?!?!?

Thanks!
Mike

 

i had that same code 2 months after buying my car brand new, got a budget y pipe and the code went away..so it was one of my precats that went bad in the stock y pipe, had the new ypipe for about 3 months now and the code never came back....and that second problem your having there should be a fuel cut Tsb for it.

 

I've been searching for the "Fuel Cut" TSB, but can't find any that say "fuel cut"...I've searched on Alldata, Edmunds, NHSTA, and the TSB sticky in this forum...

However, I did find a TSB that might be what you (and others) are referring to. But, before I go to the service department with this TSB I'd like to make sure it's the right one. Does this look right? I've been unable to find the full text of the TSB:

Component Description:
13. POWER TRAIN:TRANSMISSION:STANDARD:MANUAL NHTSA Number: 627465
Bulletin Number: NTB01018A
Bulletin Date: OCT 2001

Vehicle: 2001 Nissan Maxima
Summary:
SUBJECT REGARDING MANUAL TRANSMISSION; ON/OFF THROTTLE SENSITIVITY. *JG SUBJECT REGARDING ON/OFF THROTTLE SENSITIVITY. *JG

Thanks!

 

Hi vaaccess,
I too, (as most people in this forum know by now), have this same problem with my 2001 SE. So I can advise you some. Take it to the dealership first and get the PCM flashed per the TSB that you mentioned. It raises the tolerance of the catalyst effeciency monitoring and is a bit more forgiving about spitting out codes about that.

I took mine to the dealership and had that done but the code came back within a couple of weeks. Rather than just bend over and take the car back to the dealership and let them possibly rape me, I decided to check each of my O2 sensors.

All 4 sensors measured 4 ohms. All sensors had a good 12 Volts to the heater resistor. All upstream sensors cycled from .1 to .9 volts. All downstream sensors responded (slower) to changes in lean/rich conditions, but typically stayed at .3V. After saying all that, I believe that the cat is bad and is covered under the 80K warranty. All that to say, at least I'm prepared to walk into the dealership and TELL them to change the cat on that bank and not charge me anything for diagnosis.

Hope this helps.

 

Thanks for the tips.

The dealership upgraded my software for the PO420 error and the Fuel Cut stuff. The car drives much more smoothly in 1st/2nd gear, though it does seem to have a little less response? Is it just in my mind???

While at the dealership the service guy gave me copies of the two TSBs and I have submitted them to:
http://maxima.theowensfamily.com/tsb/

If anyone wants them sent directly to them in PDF and they are not on that page yet, just let me know!

Also, is there anything I should or should not do after my car's computer gets a fix like this? Is it re-learning driving habits, etc?

Thanks.

 

Can you list the TSB number for the Fuel Cut?

I had NTB01-018A performed awhile ago, but I'm wondering if a later one has come out.

Thanks.

 

They performed two TSBs for me.

The Fuel Cut (2000-2001 Maxima With M/T; ON/OFF Throttle Sensitivity) is still NTB01-018A.

The second one for the converter (2000-2001 Maxima MIL "On" With DTC PO420 Stored - Three Way Catalyst Function) is NTB00-070a.

 

Hi vaaccess,
Please keep me posted if the SES light comes back on. I too will post what my results are. I have an apointment with the dealership next Monday to have the cat replaced on bank 1. It will be interesting, because I told them I will NOT be paying ANY money and that I've already troubleshot the O2 sensors as being good.

 

anyone know the part number to the 02 sensor that we need if we have the code p0420??? thanks..

 

It look like I'm having this problem too, I erase the code twice and it keep coming back, it's maybe dealer time for me too...


AA