Gas cap dilema

[Abbby]

I have had a 2003 for a few years and have been battling the gas cap error code the whole time. Cleaned the metal lip very well multiple times and put on a new cap. still get the code. Recently purchasd another 2003 that does not throw the error code. The metal lip is very rusty and the old gas cap is old and the cap seal is cracked. This does not make sense. I am tempted to be proactive and clean up the metal lip to prevent future problems but do not want to create a problem. Thoughts?

[harofreak00]

Its almost never the actual gas cap that is the problem. Either the EVAP solenoid on the engine or the EVAP vent valve under the drivers rear of the car have probably failed. It could also be a leaky line.

[1tinindian]

What exactly is the code?
I have access to GM Global Connect/ Service Information, and can look into it for you.

harofreak00 is right on the money, I'm just looking for a few more details to help where I can.

Leon

[Abbby]

The code is P0440.

[drift7one]

The code is P0440.

same ine I had for some time recently. then a few days ago I cleaned up the gas cap seals and it went away. which was good, because I was thinking about doing the evap solenoid and/or vent valve with the 50% Off NAPA Auto coupon I had.

[Abbby]

I have replaced my cap and cleaned/sanded the lip a couple times. Seems unrelated to the cap on mine so I am ready to try something else.

[xdhd350]

Here is an interesting fix for that issue. Not the first thing you'd expect, but worth checking.

http://www.youtube.com/watch?v=-0gqVS6wp00

[drift7one]

smoke machines are common for finding leaks. harofreak00 made his own. I think it would be more for finding leaks in the vacuum lines. but I believe those are different codes. there's a evap emission control (P0440), small evap, and large evap leak codes. I believe the P0440 is a malfunction.

If you've read other threads, there will be nothing new here. Check and clean any corrosion around the gas filler tube. Check all of the evap lines. The best way to find the leak is to have a smoke test done, or build your own as Haro did.
http://www.pontiacbonnevilleclub.com/fo ... 44610.html

Usual suspects, in order of occurence are: Gas cap, vent valve, evap solenoid and charcoal canister.

[Ken_W]

I've noticed that this code comes and goes on its own. It seems to have something to do with the weather (or simply outside temperature). My son's 1999 Grand Am is the same way. Just when I decide to do something about it -- poof! It's gone. Both cars seem to have the problem around the same time, and lose it around the same time.

Ken_W

[drift7one]

very interesting.
off topic: humidity after rain was my Riviera's worst enemy. the coil packs would act up and begin to arc everywhere. I used to need to prop open my hood for about an hour before I went anywhere after a storm.

[drift7one]

this makes things interesting, since weather had been mentioned. it rained almost all day in NW Indiana, and I needed to fill up in gas. after filling up today, the code came back after disappearing about a week ago.