Emssions testing question

KXT said:

In my county we have OBD port testing for all 1996+ vehicles. If the rear 02 sensors are making the MIL illuminate then you fail testing [off-road mid pipe]. If I use a tuner such as the SCT xcalibrator and turn off the rear 02 sensors will I pass the emissions test? Would a better method be to use the MIL eliminators?

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use the tuner too shut off the rear o2's then you may have too wait a week or a few drive cycles too make the p1000 code go away.. the p1000 is just too let them know that the obd2 drive cycles are not compleated. and you will fail for that.

Supposedly people have talked their way out of that with the old, "my battery died a couple days ago.. would that affect these cycles you speak of?"

sgarlic said:

Supposedly people have talked their way out of that with the old, "my battery died a couple days ago.. would that affect these cycles you speak of?"

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there is no way too talk out of it in massachusetts. i don't know about your state. the p1000 code is placed as a marker indicating the codes have been cleared and the drive cycle tests are not done.

the pcm has several tests it can do on the emmision system and untill they are done the p1000 will not erase. these tests cover everything from cat monitors ( don;t worry the test will pass with them shut off) to the evap emmisions. and if the car passes it will pass any emmisions testing anywhere, so you wont have too go on a dyno.

Well, I know what you're talking about with the p1000 code. Supposedly people from several states (wish I could tell you which ones offhand, but it's on old threads,) have told the people that their battery had gone bad, and was recently replaced, causing the cycle tests to not have been completed. I'm just going by what I read, I personally don't go through emmissions testing, so I can't really interject more than that.

so you are saying in states with OBDII emision testing, u can get a hand held tuner and turn off the light for the cats and if everything else works well then you can pass the test? even without cats? how long do you have to drive the car before the P1000 code goes away?

I am a NYS inspector and heres how it works in NY, im guessing in NC its almost the same thing.

When you turn off the check engine light with a scanner (or discn. the battery), the code goes away but the computer takes a note that you did that until it has time to get new information and deside if it is running within specs, so when you plug it to the machine, it comes up as "system not ready" (basicly telling you that the sensor hasnt read long enough to decide if it is good or not) and you will fail. you have to drive the car until the sensor comes back online with a reading....but then your check engine light will come back on and you will still fail.

With the MILs however, I dont know if they just give the sensor that "system not ready" code which turns off the light, but doesnt solve the code, or it acctually gives you a false reading and trick the computer into thinking its working properly. I have them on my car, but never inspected the car with them...can anyone help me out with that?

sgarlic said:

Well, I know what you're talking about with the p1000 code. Supposedly people from several states (wish I could tell you which ones offhand, but it's on old threads,) have told the people that their battery had gone bad, and was recently replaced, causing the cycle tests to not have been completed. I'm just going by what I read, I personally don't go through emmissions testing, so I can't really interject more than that.

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Whoever told you this has no clue what they are talking about. If i see this, (1 or more sensors has that "system not ready to read" msg) by law, I have to drive the car until all the sensors come back online and then check again for codes. DO NOT DISCONNECT THE BATTERY TO CLEAR CODES- you will fail the inspection.

you can only pass an OBDII inspection if all sensors are reading and producing accepted numbers and there are no codes. As for not having cats, we are SUPPOSED to do a visual inspection, but if the computer dont read it, we dont bother....the the OBDII gives you a check engine light if it doesnt meet any standards, so it does everything itself, the test takes about 15 minutes. And there is no way to "talk out of it" because the inspection computers are hardwired into the DMV network and they acctualy aprove or fail the car, so they know before the technitian does...theres absolutely no way to pass a car unless it passes the test.

So heres the real question:
How do MIL Elliminators effect the sensor? does it give a fake reading?(you pass inspection) or does it just turn the sensor off?( you get a "system not ready" reading on that sensor and you fail

Disclaimer:: this is how it works in NY, CA and NJ.......I dont know about your state, some have no emmssions at all.

Airwolf, thanks for explaining that. I think they are goign to start the OBDII emission testing soon here in Northern,Va. So you are saying if you use a handheld to turn off the check engine light because of the offroad x and drive the car for 1 month and take it in for testing it will pass, assuming the tech doesnt look at visual of the cats?

97GTSTANG said:

Airwolf, thanks for explaining that. I think they are goign to start the OBDII emission testing soon here in Northern,Va. So you are saying if you use a handheld to turn off the check engine light because of the offroad x and drive the car for 1 month and take it in for testing it will pass, assuming the tech doesnt look at visual of the cats?

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Well, again, it depends how the scanner turns off the check engine light. If it fakes the computer to think that the sensor is reading properly, then yes it will pass. But i would bet that it only dissables the sensor and puts it in a "not ready to read" mode. This will turn off the check engine light, but it will not pass.
Like if you disconnect your battery to clear that code...it goes away for a while because the system is not ready to read, it is still gathering information, but as soon as you drive it long enough, the light comes right back. I THINK MIL elliminators and scanners just put the sensor in a "not ready to read" mode permanently so the light goes away and doesnt annoy you, but doesnt fix the problem. But, i dont know exactly how they do it, i just know how the testing works. Maybe someone should give the company who makes them a call and asks them how they work.

This whole topic has me greatly interested because i didnt take that chance, when I inspected my car i took my H-pipe w/MILs out and put back my stock one. now im almost wishing i had tried it just to see. I dont know how the MIL elliminators or programers that do the same thing work, so i cant answer that question, im just clearing up how the test works, so if anyone knows they can fill in my blank spots and we will hopefully get an answer.

AirWolf87 said:

So heres the real question:
How do MIL Elliminators effect the sensor? does it give a fake reading?(you pass inspection) or does it just turn the sensor off?( you get a "system not ready" reading on that sensor and you fail

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It gives a fake reading. I have passed ODBII testing the past two years with MIL Eliminators in NC.

jstreet0204 said:

It gives a fake reading. I have passed ODBII testing the past two years with MIL Eliminators in NC.

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awesome, well theres our blank spot filled in. If they give the computer a false reading, there will be no code because the computer thinks everything is fine and dandy with the cats and sensor. So, as an inspector, i would probably put the car in the air to do the safety inspection (if required) and check suspension and would most likely notice the lack of cats. Then After scratching my head for a few minutes over why it passed, i would say "**** it, it passed." I find it extremely unlikely that inspectors willl break balls and split hairs over this if it passes OBDII
MILs-1, State Emissions Testing-0

I could see how the MILs do that, they are a plug that sits between the sensor and wire harness, so it probably intersepts the reading from the sensor and replaces it with its own reading. However, programmers might not do that because they are not constantly connected as the computer need a constant signal from the sensors. I think those might just clear the code and it will either come back in a few miles or it will put the sensor in a "not ready to read" mode. Those of you who have handheld programers..........if you clear a code but dont do anything to fix it....will the light come back on in a day or so?

Mills worked for me this past December.

AirWolf87 said:

I could see how the MILs do that, they are a plug that sits between the sensor and wire harness, so it probably intersepts the reading from the sensor and replaces it with its own reading. However, programmers might not do that because they are not constantly connected as the computer need a constant signal from the sensors. I think those might just clear the code and it will either come back in a few miles or it will put the sensor in a "not ready to read" mode. Those of you who have handheld programers..........if you clear a code but dont do anything to fix it....will the light come back on in a day or so?

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The EEC has a variable that tells it which odb tests to run. With a programmer or a tune, you can tell the eec not to run a particular test. It isn't the same as simply clearing the code. I don't know what it would come back with on your testing equiptment if the test were turned off. I do have my EGR turned off through my tune though and it has always passed as well.

good thread! i haven't been through yet with my mils installed so i will see if it works. Failed last time cause of cel.....haven't been back in 3 yrs. Guess i should go?

If anyone know if the handheld scanners like Xcal2 or Diablo can turn off the check engine light and make it pass the OBDII emission testing please let me konw. Cause I am new in a few months for an emissions and want to know if the handheld tuners can shut it off and still pass emissions.

97GTSTANG said:

If anyone know if the handheld scanners like Xcal2 or Diablo can turn off the check engine light and make it pass the OBDII emission testing please let me konw. Cause I am new in a few months for an emissions and want to know if the handheld tuners can shut it off and still pass emissions.

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They can shut it off. But you can shut it off to by disconnecting the battery. once the codes are cleared you need to drive around for 35 miles. It will pass smog as long as the codes havent popped up in those 35 miles.

this is turning out to be a great thread.........sticky anyone????

No clearing your codes by removing the battery will not pass because the reason the codes are gone is because you erased them, but the tests are still running in the computer, and when it gets to that sensor, the check engine light will come back on, until then that test will show up as "not ready to read"

But like jstreet pointed out, the scanners erase that test from the computer all together, so that the test on that sensor no longer exists. There is no sensor to get a reading now because the test is gone and the will be no code. A completely different way than MILs, but works none the less.

try this, unplug an oxygen sensor or an EGR line and take a drive....the Check engine light will come on. you can disconnect the battery and it will go away, butif you dont fix it, it will come back again in a few miles. And until id does come back, the computer reads "system not ready to read" so it will always know when something is wrong, unless you make it think its right (MILs) or just erase that check alltogether with a tuner, but it wont pass by dissconnecting the battery.

Roger_4.6_96 said:

They can shut it off. But you can shut it off to by disconnecting the battery. once the codes are cleared you need to drive around for 35 miles. It will pass smog as long as the codes havent popped up in those 35 miles.

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So in those 35miles it wont show the P1000 code "System Not Ready" ?

So with the handheld tuner you can do the same as the MIL eliminator? Well I am getting the xcal2 soon and I willl let them konw to do that. is there a special way for the tuner to know so that it will pass emission?

97GTSTANG said:

So in those 35miles it wont show the P1000 code "System Not Ready" ?

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After the 35 miles the code should be cleared. Maybe less miles. I drove around for like 2 hours to clear the codes when it was smog day.