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P0420 code after i changed the cat converter, 54.6 miles, should i change the 02 sensorrs

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  • 33allstar Oct 15, 2010

    i replaced both , and on the way home it came back as p0420, every thing is new , i even changed the fuel pump

  • 33allstar Oct 18, 2010

    thanks

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It would not hurt the system to do so. If there was a problem with the catalytic converters, they may have damaged the O2s as well. i would replace the one in front of the cat first and reset the code. This should do it. Let me know.

Posted on Oct 14, 2010

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Hi. I provided you a useful link regarding this error code. Please click here.

Posted on Oct 15, 2010

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3 Answers

I have a p0420 code on my 2010 Jetta, already changed my 02 sensor. the car has only 70k miles on it, should I change the CAT or look at something else?


I wood look at somin else clear the code if it comes back then we should seewhat we can do as anything Changes since it has been on ? Let me Know thks for your time

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04 Altima 2.5 s w 150k changed cat 2014 1 yr later p0420 code again what r normal reads for 02 sensors? reads @ idle fluctuate @ .3V b1 sensor & .8V b2 sensor.anyone had p0420 that wasnt a bad cat


Those cars are notorious for engine problems unfortunately. The exhaust valves tend to warp from heat after around 200k miles. Therefore throwing the O2 codes. Best outcome and cost effective thing I can recommend is replacing the engine with a new or low mileage engine.

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P0420 code in a 2006 Suzuki verona Should I start by changing the downstream 02 sensor in the cat before considering a new cat? I have a leaking front flex pipe would that affect this?


Yes, the leaking flex pipe could cause this code. You need to fix that, clear the code and re test. BUT: This vehicle has had issues with the catalytic converters coming apart and ruining the engine. It can suck catalytic converter pieces into the engine. When the converter is removed, visually inspect for damage.

Sep 04, 2014 | Cars & Trucks

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2003 impala. Hard starts and fumes smell.


this is what i found for you

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensorwaveform reading should fluctuate. The downstream O2 sensoricon1.png reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Most likely, the aftermarket cat they installed is a high flow cat. This commonly causes issues with throwing that code on our cars. You can either have an OE cat installed, or just have the code deleted from the PCM by someone that has a tuner.
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1 Answer

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code p 0420 refers to cat converter system bank 1---efficiency below threshold====causes ---cat converter---wiring---HO2S (heated oxygen sensor, the one in the exhaust manifold before the cat converter)
code p 0300 is random misfires
I would suggest changing the HO2S as it reports to the ECM on exhaust content so that the ECM can adjust the air/fuel ratio
so it is logical that if that unit is not reporting correctly, the cat converter may be having trouble burning off the gasses correctly
The oxygen sensor(O2S) reads the results of the cat converter operation and helps fine tune the ECM settings

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I have a 96 Geo Metro and the code is P0420 and what does that mean.


this is a catalyst efficiency code meaning your cars computer has indicated a problem with the flow of your catalytic converter located just after the exaust manifold i the exaust system, usally these codes are triggerd by a bad or "lazy" oxygen or O2 sensor, try replacing your 02 sensors if they have some miles on them and this may cure the problem, after the repair you will need to have the check engine light cleared by a shop or auto parts store

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Jeep 2008 Commander 5.7 code p0430 What does this code mean? Thanks,


code --catalyst system efficiency below threshold bank 2 -means that the o2 sensor [bank 2 and after cat converter] is detecting that the converter in not working efficiently as it should as per specs--check the 02 sensor --if good possible exhaust leak if good --possible cat converter gone bad and since it is an 08 cat should be covered under warranty check with a dealer most converters are covered for five years doesnt matter how many miles on vehicle

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1 Answer

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If you don't have poor gas milage and loss of power, the cat is not restricted and not at fault, however, an engine misfire can also trigger that code.
Change the 02 sensor down by the cat first,( it's cheaper than a cat), see if that clears the code, if not, then go for the cat. You will already have a new 02 sensor, so that will eliminate those two. Hope this helped.

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CODE PO420 CATALTYLIC CONVERTER SYSTEM FAULT.ITS SAYING FAULTY CATALTYLIC CONVERTER.IF IT BEEN A WHILE IF YOUR CAR HAS A WHOLE LOT OF MILES ON IT.YOUR SPARK PLUG CHANGE IS DUE AT 120000 MILES. DUE A LITTLE TUNE UP CHANGE AIR FILTER AND FUEL FILTER.SEE IF YOU HAVE ANY ENGINE FAULTS BAD PLUGS DIRTY INJECTORS ANY THING UP SET FUEL SYSTEM CAUSE CAR TO RUN RICH.EXCESSIVE UNBURN FUEL WILL GATHER IN CATALYTIC CONVERTER CAUSE IT TO BURN OUT.SHORTING LIFE OF THE CATALYTIC CONVERTER.

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1 Answer

Service engine light comes on , p0420 code


the light can be caused by any one or combination of over 200 trouble codes, go to any kragen or Autozone parts store and ask for a trouble code test, it is free, then record the code(s) they come up with and post them back on fixya

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