2013 Sierra 1500 PO420 Code

[ChevyTuff 5]

My truck has new Oxygen Sensors on it (All 4) and is still throwing this code. Will these engine light eliminators work to stop this annoyance? I don't really want to spend $1000 to put new Cats on it.Any help would be greatly appreciated. 

[redvett 18]

Have you checked the operation of the O2 sensors? do that first to see if engine is running rich/lean then determine if you need to replace the Cats. If Cats. are bad it will ruin engine valves or worse. The eliminators won't fix the root of the problem.

[CamGTP 1,131]

It might stop the light from coming on if you put it on the rear o2 sensor. They do not go on the front sensors.

 

The problem will still be there though, the drivers side cat is still bad if the code is present right now. It may or may not get any worse than that. The next step in failure is the cat breaking down and slowly plugging up the exhaust.

[ChevyTuff 5]

So what you are saying is that "Only the driver side CAT Sensor can cause the PO420 Code?

Also, today I got a code PO135

So I only need to change the one on the Driver side? 

Edited February 17 by ChevyTuff

[CamGTP 1,131]

P0420 is the drivers side cat, P0430 is the passenger side cat.

 

P0135 is a circuit code on the bank 1 sensor 1 o2 sensor, that being the drivers side. Could be a bad new sensor. I only run OEM sensors, no aftermarket cheap ones.

 

Technically yes, you could just replace the drivers side cat. It would require you to cut the old cat out and weld in an aftermarket replacement. The factory y-pipe is one giant piece with 2 primary cats and 1 secondary emissions cat after the merge. The OEM part is one piece and costs a lot of money. Welding in aftermarket cats or buying an aftermarket y-pipe is your only other options. Most aftermarket y-pipes are $450-600 plus labor.

[ChevyTuff 5]

Wow, that info will. be very helpful. I will probably do as you say and try replacing the driver side 02 Sensor first. Should I replace both of the driver side ones, or just the downstream one? If that doesn't work, I will replace the individual Driver side Cat and try that.

I have a set of 4 of the chap sensors. Maybe I should send them back and get the OEM ones.These are the sensors I purchased. 

[ChevyTuff 5]

So what fro you think about me getting 2 of these and replacing the 2 Red Oxygen Sensors? These are OEM

[CamGTP 1,131]

OEM means AC Delco or Denso parts, not anything else.

 

I have part numbers of Denso 2344668 or possibly 2133866. Most auto parts stores carry them as well.

 

 

[bg1988 28]

On 2/16/2021 at 5:43 AM, ChevyTuff said:

My truck has new Oxygen Sensors on it (All 4) and is still throwing this code. Will these engine light eliminators work to stop this annoyance? I don't really want to spend $1000 to put new Cats on it.Any help would be greatly appreciated. 

   the cat is oil poisoned

  what is the temperature are you getting from the cats once it's warmed up?

[bg1988 28]

22 hours ago, CamGTP said:

P0420 is the drivers side cat, P0430 is the passenger side cat.

 

P0135 is a circuit code on the bank 1 sensor 1 o2 sensor, that being the drivers side. Could be a bad new sensor. I only run OEM sensors, no aftermarket cheap ones.

 

Technically yes, you could just replace the drivers side cat. It would require you to cut the old cat out and weld in an aftermarket replacement. The factory y-pipe is one giant piece with 2 primary cats and 1 secondary emissions cat after the merge. The OEM part is one piece and costs a lot of money. Welding in aftermarket cats or buying an aftermarket y-pipe is your only other options. Most aftermarket y-pipes are $450-600 plus labor.

 that is incorrect  P0420 will have bank 1 and bank 2   P0430  just confirms this (Not always  though)  as I had P0420 and P0430   often  and still was able to pass CALIFORNIA smog  testing   

 

 

it  turned out I had a faulty sensor else where that caused it  (faulty Barometer sensor I was getting P0069 )

 

I would check upstream as well   i.e spark plugs ,  MAF MAP   etc...  these can trigger CAT code

and the P0135 code can trigger a P0420 code

 

 

 

 

this is why it's good to verify the CAT temperature first     if it stays about 200C or so then it's bad or cracked honey  cones    it should be 325-400C minimum (unless DFCO cycle)...

 

 

Also there is other options for  catalyst converters.... such as a HIGH QUALITY  after market    MAKE sure it's a 50 state Certified model 

 here is the legit california aftermarket data base   this will help you buy a  certified catalyst converter for your truck(THAT MEANS it will work 100% compatible  No guess work)

 

Aftermarket Catalytic Converter Database

 

 

 

Also you might still have some warranty left  as emissions is 8 years/80,000 miles  ASK for a print out at a local dealer to see when the WARRANTY was punched  if your lucky  you can make a claim... and have it fixed for free

 

 

if your slightly passed that GM might help a little with the cost( or a lot)

Edited February 18 by bg1988

[CamGTP 1,131]

Going by the DTC list for the LS engines and this being a LS engine, that is what the codes are. Most OEM's use roughly the same DTC codes and yes some vehicles like fords list bank 1 and bank 2 different than GM or Dodge does.

 

 

 

 

Edited February 18 by CamGTP

[ChevyTuff 5]

New development:

Today I was sitting in Lowe's parking lot and the engine started running very rough, missing. My first thought was maybe moisture in the fuel, so I added heat brand water remover and injector cleaner. It ran better on my way home, and I haven't noticed that again yet.

 

OK, so use one of those laser thermometers and measure the outside of the cat?

 

How does this plan sound?

1. Check the temperature of the driver side cat.

2. Install new spark plugs and wires.

Install New DEnso brand Sensor in location 2 .... downstream driver side.

I'm pretty sure my warranty is gone with 132,000 miles.

 

I'm sure my warranty is long gone with 132,000 miles.

 

[bg1988 28]

1 hour ago, CamGTP said:

Going by the DTC list for the LS engines and this being a LS engine, that is what the codes are. Most OEM's use roughly the same DTC codes and yes some vehicles like fords list bank 1 and bank 2 different than GM or Dodge does.

 

 

 

 

 

thanks i have gotten the codes on a GM OBD2  both 2003 and 2008(LEV2 3way cat) models  it says bank1 and bank 2  (it will register 2 identical codes  for both p0420/p0430 besides the "bank number" being different  4 codes total.. )

 

 the only way to fully confirm it's faulty is to get a live data scanner and Confirm the operating temperature  of the converter and if  the sensor values are changing and not following...   but since he did get a different code above   that would have to be fixed first. before the  data can be verified   there is no point in paying  BIG money for nothing..  also he should verify the warranty status .  since Fed warranty is 8yr/80k.... which means 2021 is the last year ... there is also a small chance that the warranty could have been  illegally punched  as well...   

 

Edited February 18 by bg1988

[ChevyTuff 5]

 

I have a live data scanner, but I'm not very experienced with it, but I can look at live data tomorrow and see if I can find that info.

 

Update..... I couldn't understand what I was seeing on the scanner. It might as well have been in Chinese. 

 

Edited March 12 by ChevyTuff

[bg1988 28]

1 hour ago, ChevyTuff said:

New development:

Today I was sitting in Lowe's parking lot and the engine started running very rough, missing. My first thought was maybe moisture in the fuel, so I added heat brand water remover and injector cleaner. It ran better on my way home, and I haven't noticed that again yet.

 

OK, so use one of those laser thermometers and measure the outside of the cat?

 

How does this plan sound?

1. Check the temperature of the driver side cat.

2. Install new spark plugs and wires.

Install New DEnso brand Sensor in location 2 .... downstream driver side.

I'm pretty sure my warranty is gone with 132,000 miles.

 

 

I'm sure my warranty is long gone with 132,000 miles.

 

 

 

 

 

 

 

 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....

Edited February 18 by bg1988