Engine Light On

The check engine light has been on for the past month. (1997 2.2L Cav). I finally took it to Autozone and they read the code as PO440. The guy said it means a loose gas cap. I have a couple questions.

If the gas cap was really just "loose" a month ago, and for the past month I've filled up several times, and tighted it properly every time, would the light ever turn off by itself? Or is it once on, always on, even if the problem went away?

So I disconnected the battery for five minutes last night, trying to clear the light. With the gas cap very tight, I started the car, and the light immediately came back on.

Does this sound like a bad gas cap? Or maybe something else in the "EVAP" system is wrong. If the gas cap is "bad", what is likely "bad" about it? Can I tell by looking at it?

Thanks for any thoughts you all may have.
Norm

it could be a cracked vacuum line, fuel tank vent hose, loose connection, etc...

disconnecting your battery for 5 mins will reset nothing, try a few hours, maybe overnight, and if the gas cap was your problem, that light should have turned itself off a LONG time ago,

yea i think as soon as you turn it on and it is sealed it will go off after a few mins

Hey, thanks guys. I learn a lot from this forum!
Norm

Go back to autozone and have them cancel out the light, it will shut it off, if the problem is still there it will come back on again, then you'll know if it's the gas cap or not. :thumbsup:

mine has been on since I've had it. Goes off every once in awhile for like 20 miles and then comes back on. Never had them run the code, but I'm sure it's the same, Crank the cap on tight, lol.

autozone can read the lights but they are not allowed to clear them against about 100 laws, wierd enough

lol then he broke the law when he cleared mine when i had it

lol

To find the evap leak,take it to someone that has a smoke machine and it is the best way to find evap leaks.On the evap line there is a place to attach the smoke machine to with a green cap.Take the valve inside out and it is a right or left hand thread.Attach an air hose on too,there is an air fitting for an air tool type fiittingThe evap leak is found when a lot of smoke is coming out and there is the evap leak.

you cannot clear fault codes on obd2 vehicles by disconnecting the battery. if the ecm sees a fault it will trigger the check engine light. if it doesnt see that fault again it will turn the check engine light off after a pre-determined amount of ignition cycles. each manufactor is different. it could be as high as 60 ignition cycles before it turns off the check engine light. if the light stays on even after months you have an active fault that it see and it will not turn off the check engine light until repairs have been made. clearing the fault/s will do nothing if it hasnt been fixed. it will just come back on in a short time.