How to program out O2 codes and still pass OBDII emissions test?

**jcob2** · 03-02-2007, 12:47 PM

I have a 97 C5 with a blower and longtube headers. As long as I have owned the car, it has throw O2 sensor codes. I have even swapped in new sensors, and verified voltage oscillation using Autotap. They seem to work fine, it's just that they take too long to heat up, and trip the code first.

I just received my pink slip (3rd notice) in the mail from the Illinois EPA, so if I don't pass by June 20th they suspend my plates.

I have LS1 edit. There are different ways to "turn off" a code.

There is the "Does error set SES?" toggle box: Options are

On
Off

And the "Error Mode" toggle box: Options are

Type A MIL on 1st error
Type B MIL on 2nd error
Type C no MIL light
Type X turned off

In IL, I believe (please correct if wrong) that the OBDII emissions test scans for a couple things:

Is the MIL illuminated
Are there emissions related codes present
Have readiness checks been completed

I have heard that if you disable the codes in LS1edit the "wrong way" that will fail the OBDII scan because it shows the tests as not-ready, or shows them a disabled.

So the bottom line question is, using the above listed LS1 edit toggle options, how do I tune out these codes so I pass emissions by OBDII scan in Illinois?

**mrr23** · 03-02-2007, 05:21 PM

Off
Type X turned off

this will keep the light off and not report an error.

if illinois is like most states, they check for stored and current codes, along with the readiness tests being complete. anytime you clear codes, it takes about 20 key cycles to get the readiness tests completed.

**ls1alltheway** · 03-18-2007, 02:17 PM

im not sure about how to keep the car from throughing a code but i do know it takes about twenty min. to set a o2 code, and 3 key cycles. not trying to sound like a smart-ass mrr. it's just that i did state inspec. in tx for about three years. and i believe they only check for readiness, current and past code status. but ther is a loophole, you are allowed up too 3 not ready messages on the emissions test. so if you can clear the codes and and have a way to monitor the readiness status and get other systems to go ready before the o2 system than you should be good..... but check your local laws first on the test procedurs, like i said i live tx.

**BatCar** · 03-23-2007, 02:24 AM

If you want to pass....use O2 Simms...it is the guaranteed way you will pass!

**mrr23** · 03-23-2007, 06:57 AM

Originally Posted by ls1alltheway

im not sure about how to keep the car from throughing a code but i do know it takes about twenty min. to set a o2 code, and 3 key cycles. not trying to sound like a smart-ass mrr. it's just that i did state inspec. in tx for about three years. and i believe they only check for readiness, current and past code status. but ther is a loophole, you are allowed up too 3 not ready messages on the emissions test. so if you can clear the codes and and have a way to monitor the readiness status and get other systems to go ready before the o2 system than you should be good..... but check your local laws first on the test procedurs, like i said i live tx.

by setting the options to the way i stated, the SES code will not ever set. thus, no code will be stored and no light on.

**mrr23** · 03-23-2007, 06:58 AM

Originally Posted by BatCar

If you want to pass....use O2 Simms...it is the guaranteed way you will pass!

not if one fails on you. the only gauranteed way is to set the codes to off and no report.

**BatCar** · 03-23-2007, 09:25 PM

Originally Posted by mrr23

not if one fails on you. the only gauranteed way is to set the codes to off and no report.

Obviously the O2 Simms have to be good...just like real O2 sensors have to be. If the Emission Program looks for whether the rear O2 sensors are there, the Simms will look as though there are sensors there and working. Your way will not allow for this...

**mrr23** · 03-23-2007, 09:29 PM

Originally Posted by BatCar

Obviously the O2 Simms have to be good...just like real O2 sensors have to be. If the Emission Program looks for whether the rear O2 sensors are there, the Simms will look as though there are sensors there and working. Your way will not allow for this...

if the testing is looking for readings off the o2s, you are correct. if all they are doing is scanning for codes, then it doesn't matter. just depends on how deep the testing is. with your experience in that field, you would know that, as i do not.