Is there a TSB for ECU Code 0420?
Is there a TSB for ECU Code 0420?
Got a 2000 Maxima SE a little less than a month ago.
A two weeks after I got it, I had my SES light come on. Thanks to the advice from this board, I knew enough to take it to autozone and have the code pulled and the light reset. The code was 0420, something about Catalytic Effeciency Below Threshold.
About a week later, light comes on again. This was a very cold day, as was the other time it came on.
I suppose at this point I need to take it to a dealership. My question is: Is there a TSB for the 0420 code for a 2000 Max SE? I could not find one in this forum nor on any of the TSB sites.
I did see mention of a California Emissions ECU reprogramming but my car (as far as I know) does not have Cali Emmissions.
-wahoo
A two weeks after I got it, I had my SES light come on. Thanks to the advice from this board, I knew enough to take it to autozone and have the code pulled and the light reset. The code was 0420, something about Catalytic Effeciency Below Threshold.
About a week later, light comes on again. This was a very cold day, as was the other time it came on.
I suppose at this point I need to take it to a dealership. My question is: Is there a TSB for the 0420 code for a 2000 Max SE? I could not find one in this forum nor on any of the TSB sites.
I did see mention of a California Emissions ECU reprogramming but my car (as far as I know) does not have Cali Emmissions.
-wahoo
Re: Is there a TSB for ECU Code 0420?
Originally posted by WahooJames
Got a 2000 Maxima SE a little less than a month ago.
A two weeks after I got it, I had my SES light come on. Thanks to the advice from this board, I knew enough to take it to autozone and have the code pulled and the light reset. The code was 0420, something about Catalytic Effeciency Below Threshold.
About a week later, light comes on again. This was a very cold day, as was the other time it came on.
I suppose at this point I need to take it to a dealership. My question is: Is there a TSB for the 0420 code for a 2000 Max SE? I could not find one in this forum nor on any of the TSB sites.
I did see mention of a California Emissions ECU reprogramming but my car (as far as I know) does not have Cali Emmissions.
-wahoo
Got a 2000 Maxima SE a little less than a month ago.
A two weeks after I got it, I had my SES light come on. Thanks to the advice from this board, I knew enough to take it to autozone and have the code pulled and the light reset. The code was 0420, something about Catalytic Effeciency Below Threshold.
About a week later, light comes on again. This was a very cold day, as was the other time it came on.
I suppose at this point I need to take it to a dealership. My question is: Is there a TSB for the 0420 code for a 2000 Max SE? I could not find one in this forum nor on any of the TSB sites.
I did see mention of a California Emissions ECU reprogramming but my car (as far as I know) does not have Cali Emmissions.
-wahoo
Yes it does mean,
"P0420 Catalyst System Efficiency Below Threshold (Bank 1)"
http://www.ghg.net/dharrison/sae2012.htm
I don't know what exactly is causing it but I would guess the sensor that provides data to the ECU is bad or the CAT is not performing to spec.
I would say, visually inspect the area for the sensor (bank 1, I don't know which side is bank1, so inspect both) and the CAT. If you can't see any visual damage, take it to the dealer and have them look into it.
Make, it clear that you know the code (I think they charge $90 for any type of connection to the ECU), this is the 2nd occurrence and ask if the sensor is a warrantied item. I think if its the CAT it is a part of the emission system which they are responsible for.
hth
SHIFT_woosh
"P0420 Catalyst System Efficiency Below Threshold (Bank 1)"
http://www.ghg.net/dharrison/sae2012.htm
I don't know what exactly is causing it but I would guess the sensor that provides data to the ECU is bad or the CAT is not performing to spec.
I would say, visually inspect the area for the sensor (bank 1, I don't know which side is bank1, so inspect both) and the CAT. If you can't see any visual damage, take it to the dealer and have them look into it.
Make, it clear that you know the code (I think they charge $90 for any type of connection to the ECU), this is the 2nd occurrence and ask if the sensor is a warrantied item. I think if its the CAT it is a part of the emission system which they are responsible for.
hth
SHIFT_woosh
Re: Is there a TSB for ECU Code 0420?
Originally posted by WahooJames
A two weeks after I got it, I had my SES light come on. Thanks to the advice from this board, I knew enough to take it to autozone and have the code pulled and the light reset. The code was 0420, something about Catalytic Effeciency Below Threshold.
I suppose at this point I need to take it to a dealership. My question is: Is there a TSB for the 0420 code for a 2000 Max SE? I could not find one in this forum nor on any of the TSB sites.
-wahoo
A two weeks after I got it, I had my SES light come on. Thanks to the advice from this board, I knew enough to take it to autozone and have the code pulled and the light reset. The code was 0420, something about Catalytic Effeciency Below Threshold.
I suppose at this point I need to take it to a dealership. My question is: Is there a TSB for the 0420 code for a 2000 Max SE? I could not find one in this forum nor on any of the TSB sites.
-wahoo
The bulletin # is NTB00-070a dated 3-15-01.
Re: Re: Is there a TSB for ECU Code 0420?
Originally posted by Lonz
This is a known issue and is more of a "software" failure than a "hardware" failure. The ECM needs to be reprogrammed with the latest update and you should have no more problems... from this anyway. We have been filing these claims under warranty (8 years or 80k miles coverage) so as long as you are within those parameters then don't hesitate seeing a dealership to get the work done.
The bulletin # is NTB00-070a dated 3-15-01.
This is a known issue and is more of a "software" failure than a "hardware" failure. The ECM needs to be reprogrammed with the latest update and you should have no more problems... from this anyway. We have been filing these claims under warranty (8 years or 80k miles coverage) so as long as you are within those parameters then don't hesitate seeing a dealership to get the work done.
The bulletin # is NTB00-070a dated 3-15-01.
Re: Re: Re: Is there a TSB for ECU Code 0420?
Originally posted by jnovember
I was diagnosed with this same code AFTER the ECU was reprogrammed and the SES light came back on again. Was told by the dealer I needed a new cat. I walked out. SES light goes on, then off after a couple of hundred to 1,000 miles of being on. Car drives the same and no change in mpg while SES light on. Until yesterday, SES light was out for 4,000 miles. Just came on again. When it comes on, I put in a can of injector cleaner, and the light seems to go out soon after. Not sure if this is coincidence, but certainly cheaper then a new cat!
I was diagnosed with this same code AFTER the ECU was reprogrammed and the SES light came back on again. Was told by the dealer I needed a new cat. I walked out. SES light goes on, then off after a couple of hundred to 1,000 miles of being on. Car drives the same and no change in mpg while SES light on. Until yesterday, SES light was out for 4,000 miles. Just came on again. When it comes on, I put in a can of injector cleaner, and the light seems to go out soon after. Not sure if this is coincidence, but certainly cheaper then a new cat!
Re: Re: Is there a TSB for ECU Code 0420?
Originally posted by Lonz
This is a known issue and is more of a "software" failure than a "hardware" failure. The ECM needs to be reprogrammed with the latest update and you should have no more problems... from this anyway. We have been filing these claims under warranty (8 years or 80k miles coverage) so as long as you are within those parameters then don't hesitate seeing a dealership to get the work done.
The bulletin # is NTB00-070a dated 3-15-01.
This is a known issue and is more of a "software" failure than a "hardware" failure. The ECM needs to be reprogrammed with the latest update and you should have no more problems... from this anyway. We have been filing these claims under warranty (8 years or 80k miles coverage) so as long as you are within those parameters then don't hesitate seeing a dealership to get the work done.
The bulletin # is NTB00-070a dated 3-15-01.
http://www.nhtsa.dot.gov/TSBScans/sb619999.pdf
Re: Re: Re: Is there a TSB for ECU Code 0420?
Originally posted by jnovember
I was diagnosed with this same code AFTER the ECU was reprogrammed and the SES light came back on again. Was told by the dealer I needed a new cat. I walked out. SES light goes on, then off after a couple of hundred to 1,000 miles of being on. Car drives the same and no change in mpg while SES light on. Until yesterday, SES light was out for 4,000 miles. Just came on again. When it comes on, I put in a can of injector cleaner, and the light seems to go out soon after. Not sure if this is coincidence, but certainly cheaper then a new cat!
I was diagnosed with this same code AFTER the ECU was reprogrammed and the SES light came back on again. Was told by the dealer I needed a new cat. I walked out. SES light goes on, then off after a couple of hundred to 1,000 miles of being on. Car drives the same and no change in mpg while SES light on. Until yesterday, SES light was out for 4,000 miles. Just came on again. When it comes on, I put in a can of injector cleaner, and the light seems to go out soon after. Not sure if this is coincidence, but certainly cheaper then a new cat!
Re: Re: Re: Re: Is there a TSB for ECU Code 0420?
Originally posted by foodmanry
Uhhh...yes this should be covered under warranty, the emissions warranty. Or you can always get a random tech cat which I am sure is cheaper than the OEM cat.
Uhhh...yes this should be covered under warranty, the emissions warranty. Or you can always get a random tech cat which I am sure is cheaper than the OEM cat.
Re: Is there a TSB for ECU Code 0420?
I didn't get that error till after I had my ECU reprogrammed. Now get it all the time. I don't give it much thought anymore, till right before I get my Smog Check.
It mostly happens when the car is cold and I change elevation too quickly. If you leave the MIL on, it will eventually go off by itself. But, the code will still be stored on the ECU.
That's my $.02...
ADMAN

It mostly happens when the car is cold and I change elevation too quickly. If you leave the MIL on, it will eventually go off by itself. But, the code will still be stored on the ECU.
That's my $.02...
ADMAN
Well, strangely enough, last night the light went off. Right before it had gone off I had:
- Filled up with gas (93 oct, as always)
- Drove about 20 miles on highway.
- Sat with car idling for about 20 minutes (was picking someone up)
- Got back on the highway and punched it.
At some point during this it went off. I believe it was on when I parked to wait but I am not sure. It was cold as hell last night though so I don't think the temp is a factor, like I previously thought.
- Filled up with gas (93 oct, as always)
- Drove about 20 miles on highway.
- Sat with car idling for about 20 minutes (was picking someone up)
- Got back on the highway and punched it.
At some point during this it went off. I believe it was on when I parked to wait but I am not sure. It was cold as hell last night though so I don't think the temp is a factor, like I previously thought.
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Kyle Lee Cleveland
6th Generation Maxima (2004-2008)
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Sep 28, 2015 09:01 PM




