Engine Light Comes On,BUT.......

[FlaAveo5]

Ok I will try to make this short. My 'check engine' light came on like 6 weeks ago. I didn't go to Advance Auto right away to get it scanned. No time. (I could have sworn I read on here someplace, that the 2006 models and earlier ones, had a tendency to have it come on for no reason, just a fluke). So I didn't worry to much about it. And I cleared it, and it has been off for over 6 weeks. It came on today again.

When I DID have it scanned at Advance auto a few days after it came on, it read as 'no codes'. So I figured it was this fluke thing, for these years of Aveos. That fact it scanned as no codes, and it has been off for over 6 weeks. I am not to concerned.

BUT is it this a 'fluke' i read about? I am at just at 41K miles, I just hit that milestone I can go have it scanned again I guess. But, if it stays off for that long, and the first scan showed nothing,....doesn't that mean it is a 'fluke'? Opinions?

[hexskrew]

Well... That is very weird. It COULD be a fluke but it could also be something else? Maybe something that causes a long term cel but for whatever reason their scanner doesn't pick it up? I have had various issues sort of like this in the past with random cars like an old cavalier I had was having a dying throttle sensor going out but it actually worked enough to not notice a problem. It's a possibility as well that something is causing the cel but is going in and out rapidly so the computer keeps clearing it and checking it constantly? Something like this, I feel would be best worked if you got yourself an OBD2 reader and did some datalogging to try to find the cause or to randomly scan for codes in the case that it does pop up at random but keeps the light on otherwise.

If you have an android phone, you can pick up a reader off amazon for $20 or less. I detailed a little of that in another post:
http://www.aveoforum.com/forum/f82/c...08/#post206569

[06T200]

I have seen that in the past. Does it seem to change with climate at all? Mine wound up eventually being the throttle body sticking on rare occasions, I cleaned it some years back and did not change, would still get rare light for no reason, and no codes. It will eventually throw a code most likely when it is something that fails more than one 'self test'. If a certain condition does not last long enough the codes are often times cleared, perhaps to prevent false triggers? Keep an eye on it, could just be a sticky TB, or a failing sensor, or a loose connection throwing the light.

[FlaAveo5]

Well since south Fla. is HOT, and it is just getting hotter, the only 'climate change' is that we had a massive rain/hail storm like a week ago. Thats it. like 5 in of rain in 10 mins. It is now already reaching the 90's, in the sun it is way over 100,it always is. I dont know where they get the 70's from It runs fine, starts fine, same MPG, 19 on the dot.

I burned out all that DuraLube engine cleaner that was in the last tank of gas. I thought THAT made it come on, because it was so much of it. but the bottle said 'UP to 42 gallons', not use part of it for smaller tanks. So I used it all. I thought that might have been it, for making the light come on the first time EVER. Now the only thing wrong is still that damn 'braking light/shifter lockout' thing, that is still broken, it runs for like a week or so, then I have to use the emergency hole next to the shifter 90% of the time. I need to get that short traced and find out where it is, but I don't have $.02 to my name....so...not now.

i did replace that big round rubber hose, that goes from the air filter, to the 'MAF"? or the
throttle body intake? It was ripped in a lot of places, right after i had my timing belt wok done. But other than that, and put in another new battery like 5 weeks ago.

Nothing going on that I know of, except that I need a front end alignment badly, it has worn out the rim of my passenger side front tire!! The rest still look like brand new.

[06T200]

Hmm, well here on the left coast we have had record snow and rainfall, all allegedly caused by 'climate change' - who would have thunk it?

Maybe it was the cleaner, I have seen that cause a light before in a Suzuki rig, once the fuel was ran through the issue went away. Possibly the cleansers could cause a misfire of sorts and piss off the self test routines after a few miles. One of the functions of the ECM is to routinely test everything for fear of "destroying the planet" - at even the slightest hint of something off - the light goes on. If the coolant temp took one second longer to warm to the target temp = light, stuff like that is going on constantly. It amazes me my car can even make it out of the driveway without total destruction of the ozone on some days. Even if there is nothing wrong mechanically it is quite feasible to see a CEL on rare occasions just due to the constant testing.

[FlaAveo5]

i dont know what CEL means. what is it? I thought I burned out all of that cleaner, i made the tank go to almost empty. i HATE to let it go TAT low, but i wanted it all out of the system. Think it is 'hanging around' someplace?

[06T200]

CEL = Check Engine Light

If you see the light, pull the codes and go from there.

[RCA1186]

There were no codes? If you had a CEL and didn't lose battery power in-between the light shutting off and you getting it scanned there should be a stored code.

[06T200]

There were no codes? If you had a CEL and didn't lose battery power in-between the light shutting off and you getting it scanned there should be a stored code.

That is correct, there is even a 'pending codes' PID that will show any codes that are on the fence about triggering the CEL. Get a code reader and the issue should be resolved pretty easily.

[hexskrew]

Wait.. looking back at your post you said the mpg is always the same. 19 on the dot. I hope I just don't understand properly what you meant but I hope you don't mean your getting 19mpg. If so then there is definitely something wrong you should be getting between 29 and 36mgp without exception. Even when my upper 02 sensor quit working a short time ago I was getting 27mpg.