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ChevyTuff

2013 Sierra 1500 PO420 Code

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Should I install the new sensor in the downstream (Rear) on both sides?

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On 2/17/2021 at 10:21 PM, bg1988 said:

 

 

 

 

 

 

 you need the new sensor first   then you can remotely read the temp with a live data reader it's like 50$ at walmart   :)   you need to make sure the sensor is moving 

i have the AL329 it works with GM trucks

 

the O2 sensors is listed as  while reading live data  check once it's warmed up (i.e drive around)

 

Bank 1 = O2B1S1   (sensor 1)  This one should change ,  O2B1S2(sensor 2)  this should be steady (might move slightly )

Bank 2 = O2B2S1   (sensor 1)  This one should change ,  O2B2S2(sensor 2)  this should be steady (might move slightly )

 

 

 

  the CAT_temp will read in C most likely 

 

 

I made a video awhile back of it OBD2 data CAT temp and O2 sensors - YouTube

 

Don't worry I did not waste any gas it was charging up the hybrid battery and 12v battery....

OK, so I replaced both rear sensors with AC Delco parts, and still getting the dreaded PO420 Code. I also replaced the Spark Plugs with AC Delco Originals. Still getting a low speed miss part time. What do you guys think about this part to replace the Converters? They're $400 on Ebay.

 https://www.ebay.com/itm/GMC-SIERRA-1500-5-3L-Y-Pipe-Catalytic-Converters-2009-2013-BrandNew-OBDII/332336407404

 

s-l1600.jpg

Edited by ChevyTuff

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Going down this road now. 2005 here. What not to do? Buy stainless o2 extenders on ebay. There to long. So makes sensor not read right or not work at all. Took it to a shop. $450 for them to diagnose it. To tell me that $10 extender cause of problem. Then find out cat is bad. I see jegs has stainless one for $550.

 

 

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I ended up buying New AC Delco O2 Sensors and installed them. I still get the PO420 Code. I'm pissed.

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17 hours ago, ChevyTuff said:

OK, so I replaced both rear sensors with AC Delco parts, and still getting the dreaded PO420 Code. I also replaced the Spark Plugs with AC Delco Originals. Still getting a low speed miss part time. What do you guys think about this part to replace the Converters? They're $400 on Ebay.

 https://www.ebay.com/itm/GMC-SIERRA-1500-5-3L-Y-Pipe-Catalytic-Converters-2009-2013-BrandNew-OBDII/332336407404

 

s-l1600.jpg

maybe check for an exhaust manifold leak first ....if its sucking air the computer will dump more fuel in that cylinder and it will put fuel in your cats

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What's a good way to check for leaks ..... Stethoscope or maybe a hose?

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99.9% of  the time P0420/30 is a bad cat. You're making it more expensive and harder than it needs to be.

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39 minutes ago, ChevyTuff said:

What's a good way to check for leaks ..... Stethoscope or maybe a hose?

get a buddy to help i guess ....its tuff but a very good chance its part of your problem...check it before you fire the parts cannon

 

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23 hours ago, ChevyTuff said:

I ended up buying New AC Delco O2 Sensors and installed them. I still get the PO420 Code. I'm pissed.

check the temperature of the cats, when mine was broken  the temp is 200c   

 

a working one will be over 300C  to 800C

 

  get one of those cheap IR things and point it at the cat.....

 

 

most likely the CAT is poisoned with oil...

Edited by bg1988

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OK, I'll go to Missoula and buy one today. If it ends up cold with engine at operating temp, that means the Cat is bad, right? 

Thanks.

Edited by ChevyTuff

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OK, Guys. I checked the temps on the Cat Converters. I did use a Harbor Freight Laser Thermometer..... Hope it's accurate enough. It goes over 800 Degrees on my Fire Pit.

 

Passenger Side Converter          Front - 195F      Rear - 210F

Passenger Side Converter          Front - 175F      Rear - 197F

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Something seems off, that's super low.

 

Exhaust even at idle will be several hundred degrees and not 200. Usually I see 300-400.

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Something tells me this Chinese Thermometer is not accurate at all. I guess I will have to go back to town and get a better one tomorrow. I should have guessed the Chinese one is junk.  I'll check it again with a good one and report back. It's a 100 mile round trip for me to go to town again ..... but I have to get this fixed.

Thanks again guys, and I'll report again tomorrow.

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You could test it on stuff to see how far off it is. Like your own forehead. That should read 95-98 degrees.

 

Test an object outside that isn't in the sun, that should read what the ambient temp is. Get some hot water or something and see what it reads. Compare it with a meat thermometer if you got one.

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I don't trust this Harbor Freight Thermometer at all. I get a different reading on my forehead every time. I'll get a good one.

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