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

You will be okay with the 02 in there, It will just toss the Po420 code. If you have that code set to Non report SES enabled Checked, Then it would even pass a obd2 Emission check.

Originally Posted by Sinister Performance

That's a good question. I don't know what would happen if you got rid of the cat and left the rear O2 in there. The Monte I tuned on didn't have a rear O2 or a cat so I never got to try it.

I would say go ahead and try disabling the catalyst codes only (leave the post-O2 codes enabled) and then watch your fuel trims as you drive and see if it tries to run the cat diagnostic. It may try to run it but should soon quit running it as the rear O2 would show rich immediately as the test begins.

Give it a try and let us know what happens.

-ryan

Originally Posted by 01gpgt01

You will be okay with the 02 in there, It will just toss the Po420 code. If you have that code set to Non report SES enabled Checked, Then it would even pass a obd2 Emission check.

So if i do what you guys just suggested the car will only run the diagnostic once and should stop then my engine should remain running normal. The computer will just think it has a bad CAT and it wont effect the way the engine runs? Oh and also i don't have the software i am just doing a **** load of research to find a solution to this issue. Will the above SES code try to run more than once? So that me and everyone else will know what to do

In tinytuner, go to diagnostics> cat diagnostics? and there are 2 tests to set to disable, I'm not at the program right now for specifics but I know they will disable the tests.

Other than that if you leave the rear 02 plugged in and in the exhaust, you can make a 2" or so spacer so the sensor is out of the exhaust stream and then it won't throw a code like it would with no cat there and in the exhaust stream.