P0420 Catalyst System Efficiency Below Threshold [Archive] - B15sentra.net - Nissan Sentra Forum

: P0420 Catalyst System Efficiency Below Threshold


SE-R fan
10-13-2005, 12:57 AM
Tuesday morning on the way to work my SES light came on. Later that day mechanic friend of mine pulled the code for me, P0420 Catalyst System Efficiency Below Threshold (Bank 1), and mentioned that catalyst has its own warranty (5yr/80000mi) and by law dealership must perform the repairs even if the vehicle is past the powertrain. Can anyone confirm this? I've done a quick search but found nothing.

Thanks,
Mark

se-r girl
10-13-2005, 01:14 AM
I found the following on an OBD trouble code website...

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.

Not sure if this answers your question but hope it at least helps a bit.

Spec Jay
10-13-2005, 01:23 AM
isnt that the pre-cat failure? aka qr25 killer? prep for a new engine

se-r girl
10-13-2005, 01:33 AM
P0420 OBD Trouble Code
Technical DescriptionCatalyst System Efficiency Below Threshold (Bank 1)

What does that mean?Basically this means that the oxygen sensor downstream (after) the catalytic converter on bank 1 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

SymptomsYou will likely not notice any drivability problems, although there may be symptoms.

CausesA code P0420 may mean that one or more of the following has happened:

Leaded fuel was used where unleaded was called for
An oxygen sensor is not reading (functioning) properly
The engine coolant temperature sensor is not working properly
Damaged exhaust manifold / catalytic converter / exhaust pipe
Retarded spark timing

SE-R fan
10-13-2005, 09:12 AM
Thanks se-r girl. I'll definitively look more into that. I've only done a quick search without really researching the problem, I'm just wondering if that 5yr/80000mi warranty on emissions applies to Nissan.

Thanks everybody.

grifterjim
10-13-2005, 09:44 AM
Had the same code on mine, took it to dealer and they installed a new cat. as long as its under 60k miles or you got extended they should do it.

lawngn0mex
10-13-2005, 09:49 AM
If you have the stock header on the car kiss your motor good bye :(

SE-R fan
10-13-2005, 10:02 AM
Had the same code on mine, took it to dealer and they installed a new cat. as long as its under 60k miles or you got extended they should do it.
no and no :(

SE-R fan
10-13-2005, 10:24 AM
If you have the stock header on the car kiss your motor good bye :(
pre-cat huh?
I've had the recalls done but we all know that it's only masking the problem. IF the dealer replaces my cat and IF the motor still craps out down the road, do you think I have a chance proving to them that their repairs didn't do ***** and get new motor? (I know wishful thinking - I'm just thinking out loud)

JFP in PA
10-13-2005, 10:26 AM
If you have the stock header on the car kiss your motor good bye :(

Rubbish....................

Eddie@Performance
10-13-2005, 10:35 AM
Thanks se-r girl. I'll definitively look more into that. I've only done a quick search without really researching the problem, I'm just wondering if that 5yr/80000mi warranty on emissions applies to Nissan.

Thanks everybody.


Yes , yes and yes as i posted long before the following parts are covered under factory emmision warranty:

WARRANTY PARTS LIST 80,000 Miles
• Fuel injection system
Engine control module/onboard diagnostic device
• Oxygen sensor(s)
• Mass air flow sensor
• Intake manifold
• Throttle body
Catalytic converter(s)
• Exhaust manifold(s)
• Exhaust tube from manifold to catalytic
converter
• Distributor or camshaft position sensor(s)
• Crankshaft position sensor(s)
• Spark plugs, ignition coil and wires
• Ignition control module
• Evaporative emission control system
• Fuel filler neck restrictor and check valve
• Fuel tank and filler cap
• Idle air control system
• Positive crankcase ventilation system
• Exhaust gas recirculation (EGR) control system
• Pulsed secondary air injection system and valves
• Hoses, clamps, fittings, tubing, sealing gaskets
or devices and mounting hardware used in
above systems
• Vacuum and temperature sensitive valves and
switches used in above systems
• Electronic sensors and controls used in above
systems

SE-R fan
10-13-2005, 10:53 AM
Rubbish....................
Care to elaborate?

Thanks twinturboz :)

lawngn0mex
10-13-2005, 10:58 AM
Precat efficiency means the precat isn't working... the #1 reason for a QR to have that code is the precat is blown out. 0420 is the international QR goes bye bye code. moreso than 0300. (multi-cyln misfire.)

JFP in PA
10-13-2005, 11:01 AM
Care to elaborate?

Thanks twinturboz :)

Sure. DTC P0420 is triggered with the voltage switching frequency ratios between O2 sensors 1 & 2 go out of range. This could be caused by the cat failing; BUT the most common cause is one (or both) of the sensors is having a problem (loose harness connectors, wire burned/shorted, bad sensor, etc.). The FSM has always recommended checking the sensors first, before even looking at the cat(s), because they trigger the code more often than the cat(s) do. And yet, every time someone posts this code, the immedeate response is "your engine is gone". Rubbish....................

JFP in PA
10-13-2005, 11:02 AM
Precat efficiency means the precat isn't working... the #1 reason for a QR to have that code is the precat is blown out. 0420 is the international QR goes bye bye code. moreso than 0300. (multi-cyln misfire.)

Absolutely wrong, the number one reason the 0420 code is tripped (according to Nissan records) is sensor issues, not the cat failure.

SE-R fan
10-13-2005, 11:06 AM
(Gets popcorn and anxiously awaits a reply :p )

lawngn0mex
10-13-2005, 11:56 AM
Absolutely wrong, the number one reason the 0420 code is tripped (according to Nissan records) is sensor issues, not the cat failure.


do a search on this forum for stock qr's with that error code. they all got new engines, or were out of warranty and fought it. ;)

JFP in PA
10-13-2005, 12:26 PM
do a search on this forum for stock qr's with that error code. they all got new engines, or were out of warranty and fought it. ;)

I did do a search, and I the results do not agree with your proposition. Sorry. Besides which, this board is not the arbiter of the question, Nissan's are, and they do not agree either.

lawngn0mex
10-13-2005, 12:40 PM
I did do a search, and I the results do not agree with your proposition. Sorry. Besides which, this board is not the arbiter of the question, Nissan's are, and they do not agree either.


Why'd you have to go and make me an aszhole?

http://www.b15sentra.net/forums/showthread.php?t=93320

http://www.b15sentra.net/forums/showthread.php?t=112808

http://www.b15sentra.net/forums/showthread.php?t=114729

http://www.b15sentra.net/forums/showthread.php?t=111661


Seriously... all of the o2 sensor problem people on here are because of an installed aftermarket CATLESS header.

Since an o2 sensor is a part of the emmisions system, if so many failed, wouldn't there be a recall on them, not the god damn cat? According to Nissan there was no such thing as a butterfly screw problem for the longest. According to Nissan the Sentra is a reliable, well built car. According to Nissan my dick is 36 feet long and weight 700lbs. See where I'm getting.


Then again, I'm just going by what I've seen from people experiences.

JFP in PA
10-13-2005, 12:55 PM
Why'd you have to go and make me an aszhole?

http://www.b15sentra.net/forums/showthread.php?t=93320

http://www.b15sentra.net/forums/showthread.php?t=112808

http://www.b15sentra.net/forums/showthread.php?t=114729

http://www.b15sentra.net/forums/showthread.php?t=111661


Seriously... all of the o2 sensor problem people on here are because of an installed aftermarket CATLESS header.

Since an o2 sensor is a part of the emmisions system, if so many failed, wouldn't there be a recall on them, not the god damn cat? According to Nissan there was no such thing as a butterfly screw problem for the longest. According to Nissan the Sentra is a reliable, well built car. According to Nissan my dick is 36 feet long and weight 700lbs. See where I'm getting.


Then again, I'm just going by what I've seen from people experiences.

Your data is anecdotal, and therefore not statistically valid. The only true measure of how many times a 0420 code is triggered and results in an engine failure is Nissan’s records. Their “population sample” is significantly larger than what has been posted on this board, and selected in your list. I contacted a former employee, who now works for Nissan engineering, and had him search this issue. His results indicate that for every 5 times a code 0420 triggered, more than 4 incidents are O2 sensor related. And that is from a population of incidents rather larger than you listed. Sorry, but that data cannot support your proposition.

lawngn0mex
10-13-2005, 12:58 PM
Your data is anecdotal, and therefore not statistically valid. The only true measure of how many times a 0420 code is triggered and results in an engine failure is Nissan’s records. Their “population sample” is significantly larger than what has been posted on this board, and selected in your list. I contacted a former employee, who now works for Nissan engineering, and had him search this issue. His results indicate that for every 5 times a code 0420 triggered, more than 4 incidents are O2 sensor related. And that is from a population of incidents rather larger than you listed. Sorry, but that data cannot support your proposition.


Did you need to use a bigger font?

DId you ask them how many of those with o2 sensor issues had headers? ;)


Also, I like how you consider my evidence to be anecdotal... considering you haven't provided anything but "I know a dude man... and he works at Nissan."


Give me a break. Anyone who is stock and gets a 0420 I would say, the majority of them will need new motors.

JFP in PA
10-13-2005, 01:03 PM
Did you need to use a bigger font?

DId you ask them how many of those with o2 sensor issues had headers? ;)

No, I didn't specifically ask that, but interestingly, many of the O2 sensor triggered codes were caused by wiring issues, when the harness burned on a "modified exhaust system" (I don't have an actual count, but can get it if you would like it).............

lawngn0mex
10-13-2005, 01:04 PM
No, I didn't specifically ask that, but interestingly, many of the O2 sensor triggered codes were caused by wiring issues, when the harness burned on a "modified exhaust system" (I don't have an actual count, but can get it if you would like it).............


Thanks... that proves my point enough. ;)

JFP in PA
10-13-2005, 01:07 PM
Also, I like how you consider my evidence to be anecdotal... considering you haven't provided anything but "I know a dude man... and he works at Nissan."




It is anecdotal because it represents a limit sampling of a limited audience. Nissan's represent all claims for service, warranty or otherwise, and represent a much larger cross section of incidents. And the gentleman in question that provided the data is a respected automotive engineer, a registered member of the SAE, and a senior engineer with Nissan; not a "dude".

JFP in PA
10-13-2005, 01:10 PM
Thanks... that proves my point enough. ;)

How so? The data supports that a limited number of 0420 codes result in engine failures and replacements............................and that most are the result of sensor issues.

lawngn0mex
10-13-2005, 01:11 PM
It is anecdotal because it represents a limit sampling of a limited audience. Nissan's represent all claims for service, warranty or otherwise, and represent a much larger cross section of incidents. And the gentleman in question that provided the data is a respected automotive engineer, a registered member of the SAE, and a senior engineer with Nissan; not a "dude".



You have to understand where I'm coming from... do you? btw. Thanks for coming back down to normal earth fonts.

JFP in PA
10-13-2005, 01:13 PM
do a search on this forum for stock qr's with that error code. they all got new engines, or were out of warranty and fought it. ;)

Remember this quote? It implies that every 0420 code results in enigne failure/replacement. A review of a larger data sample does not support that supposition.......................

SE-Mark
10-13-2005, 01:26 PM
Why hasn't anybody suggested getting a compression test?

If the engine passes compression, get a new o2 sensor and a new header (the new header is to prevent the precat disintegration failure, and will also get you some more power).

If the engine fails compression, start your fight with Nissan. When the fight is over, and your car is running again, get a header.

It seems like the consensus is that the 2002 (and maybe 2003) QR25 Sentras should have their precats removed as a preventative maintenance item.

razz
10-13-2005, 04:17 PM
If it's the pre-cat, it's covered under the emission warranty. If you have a problem with your dealer, call Nissan. I know someone who got 0420 code on her GXE and got pre-cat replaced under the emission warranty. Let us know how it turns out.

rede2roll
10-13-2005, 07:47 PM
Tuesday morning on the way to work my SES light came on. Later that day mechanic friend of mine pulled the code for me, P0420 Catalyst System Efficiency Below Threshold (Bank 1), and mentioned that catalyst has its own warranty (5yr/80000mi) and by law dealership must perform the repairs even if the vehicle is past the powertrain. Can anyone confirm this? I've done a quick search but found nothing.

Thanks,
Mark

The answer to your question is in your owner's manual, listed under federal vehicle emissions control. The warranty term for catalytic converter(s) is 8yrs/80K miles.

rede2roll
10-13-2005, 07:51 PM
Yes , yes and yes as i posted long before the following parts are covered under factory emmision warranty:

WARRANTY PARTS LIST 80,000 Miles
• Fuel injection system
Engine control module/onboard diagnostic device
• Oxygen sensor(s)
• Mass air flow sensor
• Intake manifold
• Throttle body
Catalytic converter(s)
• Exhaust manifold(s)
• Exhaust tube from manifold to catalytic
converter
• Distributor or camshaft position sensor(s)
• Crankshaft position sensor(s)
• Spark plugs, ignition coil and wires
• Ignition control module
• Evaporative emission control system
• Fuel filler neck restrictor and check valve
• Fuel tank and filler cap
• Idle air control system
• Positive crankcase ventilation system
• Exhaust gas recirculation (EGR) control system
• Pulsed secondary air injection system and valves
• Hoses, clamps, fittings, tubing, sealing gaskets
or devices and mounting hardware used in
above systems
• Vacuum and temperature sensitive valves and
switches used in above systems
• Electronic sensors and controls used in above
systems


You need to review your info a little better. You are correct in stating that the above listed item are emissions related. But, only catalytic converters and ECM/OBD devices are covered under 8yr/80 K miles.

curtietang
12-29-2005, 04:39 PM
Hello all...i am new to the board and i am here for this very reason 0420....I am working on my sisters 2000 GXE and am trouble shooting the 0420 code.....this engine is completly stock and has right at 100K.....I am trying to solve this problem and need some tips to get started.....

-so you guys are probably going to reply and say my motor is trashed...well i can test compression....what is optimum compression in each cyl?

-what else should i check before i begin replacing parts?

lets use this as a test to better determine the causes of this trouble code.

again this is a unmodified 2000 GXE 1.8L DOHC