Removing rear O2 sensor on 01-newer PCMs -- Things you should know

I've been reading through this thread back and fourth trying to figure out what's actually relevant. I'm using hpt on a 06 grand Prix gxp. I'm hoping anyone else with hpt can verify that just turning off dtc's and post cat and rear 02 tests is the way to go.?

from what im reading, it can be accessed from a 05+ file through tiny tuner. the 04 and 05 are different ( have diff dtc codes) so i have to manually transfer files over and change dtc 1 by 1 to get to the option i need.

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Originally Posted by slick2500

So I just found this on ZZP - Angled O2 bung #

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Do I need one of these for my 2000 GTP? Want to delete cat but not lose MPG.

Spark plug non-foulers are cheaper and function based on the same principal. Google it and you'll find it the first try. Also, this is already listed in this thread. Actually reading the thread helps a lot. ;-)

None of that stuff is needed Steve just buy an overkill tuned PCM and ask him to disable all of the catalytic converter codes that's what I did and I don't have any issues and my gas mileage is still the same. Plus my ECU reports no errors at all times even without the cat because of the overkill PCM being tuned and those codes being disabled and as a result I pass inspection every single time. Before anybody says anything negative I wouldn't be telling him this if it didn't work on my car my cars 2002 anything beyond a 2002 I believe the catalytic converters are not able to be removed/disabled. And if you're so inclined to look at what I'm talking about you can check out my bin file from HP Tuners if you'd like just message me and I can send it to you. And if you're thinking about buying HP Tuners its a great investment and I wouldn't trade it for anything in the world it's definitely worth the money so with that being said you can learn a lot if you have the money to buy it.

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Originally Posted by slimguns

Actually reading the thread helps a lot. ;-)

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FYI I read the entire thread so I missed it. Thanks for the help.

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Originally Posted by Steve V

Do I need one of these for my 2000 GTP? Want to delete cat but not lose MPG.

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97-00 doesnt care about the rear o2 sensor for fueling. 01+ have the cat diag in the PCM that when the cat and rear o2 are removed will effect gas mileage.

On 01+ the cat can always be removed, but will require a tuner to shut off the diag and the code, the 97-00 will just need a tune to shut off the code and stop the SES from coming on.

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Originally Posted by Fivefingerdeathpunch

97-00 doesnt care about the rear o2 sensor for fueling. 01+ have the cat diag in the PCM that when the cat and rear o2 are removed will effect gas mileage.

On 01+ the cat can always be removed, but will require a tuner to shut off the diag and the code, the 97-00 will just need a tune to shut off the code and stop the SES from coming on.

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The solution to this is just to remove the cat but not the two sensors so that the ECU will run the diagnostic process and it'll fail but the ECU will not report the code. Since the diagnostic sequence will run and then fail the ECU will not continue to run the diagnostic test which in turn will result in no excess fuel being used once said test is ran. Fuel is only wasted if that test is continued with no definitive result to be recorded as a pass or fail by the ECU. Like FFDP said the diagnostic procedure and cat codes will need to be turned off by someone with HPTuners.

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Originally Posted by apierce1289

The solution to this is just to remove the cat but not the two sensors so that the ECU will run the diagnostic process and it'll fail but the ECU will not report the code. Since the diagnostic sequence will run and then fail the ECU will not continue to run the diagnostic test which in turn will result in no excess fuel being used once said test is ran. Fuel is only wasted if that test is continued with no definitive result to be recorded as a pass or fail by the ECU. Like FFDP said the diagnostic procedure and cat codes will need to be turned off by someone with HPTuners.

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Uh no..... you will run rich as hell Because the test comes up incomplete. It will then try to richen up the mixture in order to keep the cat from being burned up

I've never noticed anything wrong with my car so I can't vouch for that. But I'll scan it with hptuners and take a look. Highly doubt I'll find anything but I'll look when I have some spare time.

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I decided to take a look with my torque obd2 app on my android phone because I haven't had time to grab my laptop and catalyst emissions check has been completed (while I have known that this emissions check has been completed I wanted to show you proof anyways so that people know that it does not show as incomplete). Please note that my cat is removed. So There's proof right there that the catalyst emissions check is able to complete as long as everything is set up in the ECU correctly with HP Tuners :)

http://img.tapatalk.com/d/13/04/22/7esymeza.jpg

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I have an 02 GTP.
Going with TOG headers and TOG stainless 3" with cat. Tuned PCM with Cat codes, rear o2 sensor codes, and egr codes all removed etc...
Is it beneficial to run an o2 emulator to keep my fuel trims? Or do I need the real rear o2 sensor to not run flat out rich?

I tried reading through all 9 pages and deciphering the correct information but still didnt come to a conclusion.

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Originally Posted by apierce1289

I decided to take a look with my torque obd2 app on my android phone because I haven't had time to grab my laptop and catalyst emissions check has been completed (while I have known that this emissions check has been completed I wanted to show you proof anyways so that people know that it does not show as incomplete). Please note that my cat is removed. So There's proof right there that the catalyst emissions check is able to complete as long as everything is set up in the ECU correctly with HP Tuners :)

http://img.tapatalk.com/d/13/04/22/7esymeza.jpg

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Just saw youre response dude you never said you had HP tuners and that it was already taken care of my post was regarding If you were on a factory calibration still and removed the cat while leaving the rear 02 active

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Originally Posted by Yarbeau

I have an 02 GTP.
Going with TOG headers and TOG stainless 3" with cat. Tuned PCM with Cat codes, rear o2 sensor codes, and egr codes all removed etc...
Is it beneficial to run an o2 emulator to keep my fuel trims? Or do I need the real rear o2 sensor to not run flat out rich?

I tried reading through all 9 pages and deciphering the correct information but still didnt come to a conclusion.

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As long as you have the catalyst diagnostic test shut off, you don't need the rear O2.

You can't shut off the test for the rear o2 catalyst. You have to disable all the codes that have to do with the catalyst emissions check and set them to no error report by removing the rear o2 sensor you're going to stop it from completing the test as long as it completes the test ( as long as its pass or fail it won't matter because it won't run again until you clear all the codes inside of the computer) it'll just reported that nothings wrong.

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Tiny tuner shuts test off.

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Originally Posted by FoSHO99

Tiny tuner shuts test off.

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I did not know that where can I get tiny tuner?

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Originally Posted by apierce1289

I did not know that where can I get tiny tuner?

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Here.....

I have read through all 9 pages of this damn thread 3 times now. i am not sure of the answer to my question STILL. i bought an 01 GTP, the cat has been removed, i have a P0420 code, thats it. i have a bluetooth OBD2 dongle and Torque Pro app. everything has passed except for the cat test, due to that code/no cat. i live in MA so i will need to pass emissions. assuming they dont do a sniffer or a visual check(im pretty sure i can go to a place that wont do sniffer/visual), just a scanner check, how do i pass inspection without buying a friggin cat and having it welded in and without spending tons of money on a pcm or a tune? ive heard the code sometimes comes up with an aftermarket high flow cat, and 2 spark plug non foulers on the rear o2 will slow it down enough to pass, but what about with no cat at all? if non foulers wont work, can i just download the free tiny tuner and set the diag to pass so i can get a sticker?
***i am assuming since the test has run and failed to pass and set a code, it is not continuously running and fudging up anything and dumping fuel. if this is the wrong assumption someone let me know!"

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Originally Posted by jjmitch87

I have read through all 9 pages of this damn thread 3 times now. i am not sure of the answer to my question STILL. i bought an 01 GTP, the cat has been removed, i have a P0420 code, thats it.

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You and me both. I read the whole thread...twice, and still keep reading both conflicts in what to do, and conflicts between a few responders, which did nothing but confuse me further...lol :th_shakinghead2:

I have HPTuners, well used and understood on my other V8 LS based vehicles.
No intention of buying any other program or software, whatsoever...
Never tuned a positive displacement supercharger before...but have tuned centrifugal supercharged cars of the non-GM brand...

I have bought the HPTuners tuning license for my son's "new" 2001 GTP.

He also has the recurring P0420 code, I believe due to the converter being gutted out, and car is due for emissions inspection.

If I am understanding correctly, if I change the rear converter/rear O2 sensor codes to NO ERROR REPORTED, and UNCHECK SES (or MIL) light, then the PCM will try the cat test once, then fail, but not keep trying the "test"???

Without any Tiny Tuners or whatever else, is this my best option for not dumping fuel and/or failing the emissions test?

Thanks in advance. :th_thumbsup-wink: