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post #1 of 15 (permalink) Old 12-13-2017, 11:25 AM Thread Starter
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Po420 Code

ok so that last few weeks i have been getting this code. a few times i got p0135 and p0130 which leads to front 02 sensor. p0420 leads to cat. so i have been doing some research and i see a bunch of guys saying to try lacquer thinner in the gas to see if that clears out the code due to possible clogging of the media. so before i dump this in the tank i figured i would run it by you guys to see if there is any merit to this of is it some much bs? if it works then i will give it a try also some say to move the lat 02 out of the stream by adding 2 spark plug extenders. i have done that to a geo metro when i was experimenting with water into hydrogen. that helped to keep the front sensor off but did not help with mileage as the 02 just compensated for the lack of 02. also i have tried acetone for that metro and it did not help so that makes me ask before i just dump this into the tank. thanks

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post #2 of 15 (permalink) Old 12-13-2017, 01:55 PM
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P0420 Catalyst System Efficiency Below Threshold (Bank 1)

This means your front HOČ is arriving at it's end of life, you may have a bit of cat contamination but this should clear once you change the HOČ sensor and drive it for a few hundred miles.

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post #3 of 15 (permalink) Old 12-14-2017, 05:03 AM Thread Starter
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coby7 i have a new 02 sensor in the front. i just changed it about a week ago and being i do not drive this car much i just reset the code. if you recall i asked if that code p0130 would reset itself but no one replied and said either way so i just reset it. it was a rockauto 02 sensor.

so it sounds like your telling me i have to change the front one again or the back one? or are you saying once the front one has been changed i need to drive it some time to get the cat back to normal? if that is the case then it may take quite a bit as the car maybe see's 20 miles a week.



i confused being the code leads to cat inefficiency? thanks coby7

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post #4 of 15 (permalink) Old 12-14-2017, 05:39 AM
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Did you get an ACDelco HOČ?

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post #5 of 15 (permalink) Old 12-15-2017, 06:37 AM Thread Starter
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Quote:
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Did you get an ACDelco HOČ?
don't know if it was or not if i can find the package and it has any of that information on it maybe i will be able to tell. i reset the light the other day and i drove 60 miles yesterday on a visit to kids and it has not returned so maybe it just had to be driven. i will let you know if it returns and then go get the ac delco 02 sensor if the code leans to that. thanks

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post #6 of 15 (permalink) Old 12-15-2017, 07:17 AM
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People on here have had bad luck with Bosch and NTK where they wouldn't last very long or wouldn't work at all. Chances are it just needed a good run especially if you touched the end of the sensor with your hands.

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post #7 of 15 (permalink) Old 12-15-2017, 12:53 PM
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Yup can't be any other brand. Has to be a.c. Delco the rest fail and good luck sending them back.

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post #8 of 15 (permalink) Old 12-16-2017, 08:49 AM Thread Starter
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again thanks, if it keeps showing up i will just not mess around and will just go and get one from ac delco. i have to see if i can find the box this one came in but by now it is most likely in the landfill. and i don't think the place i got it can tell me. anyway thanks for the help. if it does return i will post it and the codes that showed up for more help in troubleshooting.

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post #9 of 15 (permalink) Old 01-17-2018, 12:12 PM Thread Starter
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so i got the p0420 code again after my first post on this back in sept. i did not remember the make of it but i do not drive the car much at all may have put 200 miles on it since then. and now in the last 2 days i returned back to work and now i got the code again. so i must have got the wrong one, seems it shout not have went out this fast.

so rock auto has them for like 50.00 or might i want to vist advance auto and pay 80.00 but then if it fails i may have a warranty? or what parts store offers a warranty.

last time i went thru the 02 sensor issues was on a 95 lebaron and i spent hundreds trying t get that one corrected and the last one came from the dealer and they did not stand behind it either. if that is the case and i get another one and i get the code again i just put tape over the light and forget it. tired of all the money on stupid stuff.

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post #10 of 15 (permalink) Old 01-17-2018, 12:45 PM
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Rock auto is where most buy them. I have a business account so I get discounts at the dealership so I went there. 120k km later and no issues.

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