Emission testing (live, codes, cost of)

[shadow91]

Just got notified my car has to be tested for emissions. The service engine light is on and has always remained on even after repair of the car. What effect will this have on testing and exactly what do they do and look for in order to pass? I am worried and need my car for transportation.

[Ponderosa]

They won't even test you if the light is on. The emissions test consists of using a reader to look at stored codes. Do 1 of two things: take it to Autozone and they can tell you what the code is and what it means. They don't charge you for that. They can also clear the code and turn out the light. The other thing is to disconnect the battery for a couple minutes. That will clear the code and the light will go out. HOWEVER: you will not pass emissions after either clearing the code with a reader or by disconnecting the battery. You must go through some driving cycles with your car where the computer runs the full range of diagnostics. This can take a few days of normal use. If the light comes back in that time, your problem was not fixed (or you have a new one) and you will flunk emissions until it is fixed, the light goes out and stays out.

Note: The light will eventually go out on its own after making repairs even if the service facility does not reset it. So, if it has been a while since you have had it serviced and you have been driving under a variety of conditions like stop and go, freeway, idling for a while etc, and the light is not out that is a bad sign that you still have problems. Take it to autozone. It could be something as minor as a bad gas cap.

[maverick974]

Originally Posted by Ponderosa

They won't even test you if the light is on. The emissions test consists of using a reader to look at stored codes. Do 1 of two things: take it to Autozone and they can tell you what the code is and what it means. They don't charge you for that. They can also clear the code and turn out the light. The other thing is to disconnect the battery for a couple minutes. That will clear the code and the light will go out. HOWEVER: you will not pass emissions after either clearing the code with a reader or by disconnecting the battery. You must go through some driving cycles with your car where the computer runs the full range of diagnostics. This can take a few days of normal use. If the light comes back in that time, your problem was not fixed (or you have a new one) and you will flunk emissions until it is fixed, the light goes out and stays out.

Note: The light will eventually go out on its own after making repairs even if the service facility does not reset it. So, if it has been a while since you have had it serviced and you have been driving under a variety of conditions like stop and go, freeway, idling for a while etc, and the light is not out that is a bad sign that you still have problems. Take it to autozone. It could be something as minor as a bad gas cap.

Depends on the car. My car won't clear the codes by just disconnecting the battery. I have to remove the negative cable from the battery and touch it to the positive cable. That's the only way to clear the codes and reset the computer for my particular car and many others are the same.
Just sayin'

[kell490]

If your car is 96 or newer it is ODB2 that is the one when you go to the emission place they will only plug in and search for codes they don't even look to see if you have Cat's installed. If you don't have any codes then they will pass you if also your gas cap and tank pressure test are okay. If they find a code they will fail you and you get one free retest. If your car is older then 1996 then the code doesn't matter and neither does the check engine light they will run it on the rollers and check the tail pipe for emissions that exceed the limits. I know this because my Brother 91 bronco passed with the check engine light on we still can't figure that one out it has other issues. 1996 and older is called ODB1 it's older technology and codes are not used for emission testing in Arizona. What you could do is go to Autozone and have them pull the codes and clear them I had one guy that refused to clear it. Later I got my own code reader from Harbor freight and I cleared my own code. I would start with Autozone and see what the code is first and have them clear it. See how long it takes for it to come back on it might take awhile. If it does then have him clear it again and go straight to the emission place. After you get the codes you can call around and ask repair shop what it will cost to fix the issue once you know what part is bad from the code. The code that yours is throwing might be an easy fix you never know I had a bad O2 sensor it was an easy fix just needed one wrench and 10 minutes.

[caryberry]

Originally Posted by shadow91

Just got notified my car has to be tested for emissions. The service engine light is on and has always remained on even after repair of the car. What effect will this have on testing and exactly what do they do and look for in order to pass? I am worried and need my car for transportation.

You'll have to fix or have someone repair your car. It will not pass.

Its just the cost of doing business...and God knows, the lack of air quality in the Valley should be enough incentive.

[mir86]

My check engine light comes on and off and I've had my car for 5 years. I have to run it for a few days after I turn off the light just to get it tested for emissions???? that's crazy.

[grmi66]

When I lived in Idaho I could get my old car through emissions despite pulling up a couple of codes because the reader that they put in the tail pipe said my car was clear. Moved to Arizona and found that if you have any codes they will not let you pass emissions. The cost to bring my car into compliance was more than the car was worth and I just sold the car. Luckily I had already started saving money for a down payment on a new car.

[Ponderosa]

Originally Posted by kell490

If your car is 96 or newer it is ODB2 that is the one when you go to the emission place they will only plug in and search for codes they don't even look to see if you have Cat's installed. If you don't have any codes then they will pass you if also your gas cap and tank pressure test are okay. If they find a code they will fail you and you get one free retest. If your car is older then 1996 then the code doesn't matter and neither does the check engine light they will run it on the rollers and check the tail pipe for emissions that exceed the limits. I know this because my Brother 91 bronco passed with the check engine light on we still can't figure that one out it has other issues. 1996 and older is called ODB1 it's older technology and codes are not used for emission testing in Arizona. What you could do is go to Autozone and have them pull the codes and clear them I had one guy that refused to clear it. Later I got my own code reader from Harbor freight and I cleared my own code. I would start with Autozone and see what the code is first and have them clear it. See how long it takes for it to come back on it might take awhile. If it does then have him clear it again and go straight to the emission place. After you get the codes you can call around and ask repair shop what it will cost to fix the issue once you know what part is bad from the code. The code that yours is throwing might be an easy fix you never know I had a bad O2 sensor it was an easy fix just needed one wrench and 10 minutes.

Having it cleared and heading to emissions will not work. Clearing resets all of the unit tests. The reader will show a "not ready" status until all the sub-tests have completed. They will not pass you (or even continue the test) unless your OBD is in ready status. That is why you have to drive it around a while after fixing the problem. IIRC, one of the unit tests is a cold start test where the ambient temp has to be below 86. One might have to wait until October for that around here!

[Ponderosa]

Originally Posted by maverick974

Depends on the car. My car won't clear the codes by just disconnecting the battery. I have to remove the negative cable from the battery and touch it to the positive cable. That's the only way to clear the codes and reset the computer for my particular car and many others are the same.
Just sayin'

It might have a capacitor then then that keeps the code memory alive. It won't hurt to do that so one can try that as well. It was not necessary on any car I have owned, but then I would usually let it sit a while because I was working on it. Capacitors discharge normally over time. I suppose it is possible that some cars have non-volatile memory for codes, as well. In any case, a reader has the ability to clear them.

[kell490]

[quote=Ponderosa;31454764]Having it cleared and heading to emissions will not work. Clearing resets all of the unit tests. The reader will show a "not ready" status until all the sub-tests have completed. They will not pass you (or even continue the test) unless your OBD is in ready status. That is why you have to drive it around a while after fixing the problem. IIRC, one of the unit tests is a cold start test where the ambient temp has to be below 86. One might have to wait until October for that around here![/QUOTE


Would depend if the problem is intermittent or not if the code doesn't come back for a week of driving then it might work I wanted to see if the OP could clear it and see if the problem comes back again.