2013 Sierra 1500 PO420 Code

swathdiver · March 29, 2021

8 hours ago, ChevyTuff said:

Swap the Front, not the Rear sensors? Also, on the battery, I was getting the PO420 code before I changed the battery, but I'll have this new one checked.

I doubt P0420 has anything to do with your battery. All of those other problem could be associated with a bad battery or grounds. Some problems seem to be related but you have multiple issues going on here.

ChevyTuff · March 29, 2021

I swapped the Front 02 Sensors last night. I'll drive to town today and see if that P0030 code comes back. Where can I buy one of those Tech-2 meters?

swathdiver · March 29, 2021

45 minutes ago, ChevyTuff said:

I swapped the Front 02 Sensors last night. I'll drive to town today and see if that P0030 code comes back. Where can I buy one of those Tech-2 meters?

Ebay usually, look for US sellers but some of the Chicom ones are reputable and have good reviews. Can also buy from ChinaCarDiags and places like that. They run $300-$350 or so. Make sure software is 33.004.

Is your Sierra an NHT by chance?

ChevyTuff · March 29, 2021

1 minute ago, swathdiver said:

Ebay usually, look for US sellers but some of the Chicom ones are reputable and have good reviews. Can also buy from ChinaCarDiags and places like that. They run $300-$350 or so. Make sure software is 33.004.

Is your Sierra an NHT by chance?

I just watched a video on the GM Tech2, and it looks like I would be wasting my money unless I took a course on how to use it. I only have Apple Mac and iPd also.

swathdiver · March 29, 2021

2 minutes ago, ChevyTuff said:

I just watched a video on the GM Tech2, and it looks like I would be wasting my money unless I took a course on how to use it. I only have Apple Mac and iPd also.

It's not hard to learn, I didn't take any classes, just bought and used it. If you need to do programming, then you can connect it to the internet at ACDelco's TDS system.

ChevyTuff · March 30, 2021

Well, I took my truck to the Chevy Dealer in Missoula (Karl Tyler) and here's what they're telling me. They found the oil. cap missing, I have no idea what happened to that. They say this could set off codes and there was a code on bank 2. They cleared the codes.

They are saying that the Cats I had installed are not original GM Cats, and that I need to install the factory Cats. I paid almost $600 for these Cats, and paid a muffler shop $250 to install them. They told me the parts alone for them to install GM Cats is over $1700

Edited April 1, 2021 by ChevyTuff

CamGTP · March 31, 2021

Not having factory cats won't cause a misfire code or an upstream o2 sensor code.

Only if you are still getting a P0420 or P0430 would it need OEM cats. But at that point there is no way I'd spend $1,700 for new cats when you could just tune the computer and shut off those codes forever for like 1/3 the price.

ChevyTuff · March 31, 2021

This is my bill from our dealership. 3 pages, so I will have to do 3 posts

$1000.00 and they say now that it's the aftermarket Cats causing the problem. And the codes are still on.

ChevyTuff · March 31, 2021

ChevyTuff · March 31, 2021

So this is where it stands now. They found Codes PO523 / PO155 / POO59 and POO50 ..... All on Bank 2 Sensor 1

They charged me 8 hours labor total, and they did not find the main problem with the mis-fire. Most of the $800 plus labor was their diagnosing the misfire, and they didn't fix it. They blame it on the after market cats.

I am happy with the tranny flush, and the door wire fix.

Tell me what you guys think. I am desperate here.

Edited March 31, 2021 by ChevyTuff

CamGTP · March 31, 2021

The part about needing new cats still doesn't add up to me. If the fuel trims are still negative that means it's running rich on that bank. That can be caused by the misfires. Now if the bank 2 sensor 2 is reading really low mv that would mean that the sensor is showing lean.

Values of like .900mv is rich and ~100mv is lean. How can the front o2 sensor report negative fuel trims (rich) but the rear o2 sensor report lean??

I have never seen new cats fix that problem. The only codes that should make the SES light come on from non working cats are the cat inefficiency codes themselves.

ChevyTuff · April 1, 2021

I have to agree that the Cats are probably not the culprit. Everyone I have talked to has said these after market Cats work just fine. I don't know what to do at this point. I arguably paid the bill and picked up my truck today. It still misses and runs crappy just like before, especially when I drive it, then park for a while, then drive it again. Code P0050 was reset when I parked it and started it again at home.

Could it possibly be something like one of these and the shop tech just doesn't know what he's doing?

Edited April 1, 2021 by ChevyTuff

tbarn · April 1, 2021

Seems to me they charged 1.0hr diag. $139.00. Roughly $800 was spent on oil pressure sensor replacement, trans flush and wiring repair.

P0050, P0059, P0155 are all bank 2, sensor 1 heater codes. Shouldn't cause a drivability problem especially on a warm engine. Cats could not cause these codes. Pull the passenger side oxygen sensor in or near the manifold. Is it soot covered? possibly a leaky injector ( internal ). Here is a schematic for oxy sensors if it helps.

ChevyTuff · April 1, 2021

I just had the 2 front sensors out and swapped them around. I didn't see any oil on the sensors, and they are brand new Delco sensors. Something is causing it to set the codes and to run very poorly.

tbarn · April 1, 2021

These 3 codes can only be caused by a bad sensor, wiring or ECM. You or someone needs to do a deep dive diagnostic. Whether or not they cause a rough run condition is another question.