How to fix an Evaporative Emission Control System Malfunction - OBD II Code P0440??

My SES light came on a few days ago. I immediately tightened my gas cap and then refueled that afternoon. The light has not gone off for 4 days now. I took it to AutoZone yesterday and had it scanned and it came up as P0440 (which is Evaporative Emission Control System Malfunction).

The guy at AutoZone (who seemed like he wasn't the brightest bulb in the bunch) said that it must be that the gas cap is leaking and not holding pressure.

Is that the first thing I should start out with? I'm planning on going to the dealer after work to get a new gas cap and installing it since it's a relatively cheap attempt to fix it. If that solves it, how long will it take before the SES light goes out? Will it be immediately? Should I reset it after installing the new cap? If that doesn't work, what else should I try or should I just bite the bullet and take it to the dealer?

Anyone else had this code come up and what did you do to fix it?

BTW, I have a 2000 Pontiac Grand Am, if it matters.

Thanks for the help.
Matthew

P0440 is a generic code for Evaporative Emissionm Control System Malfunction... pretty much for all makes. It takes 1 malfunction to create a pending DTC... at 2 consecutive malfunctions the MIL(Malfunction Indicator Light){Check Engine Light, etc.} Ok, after you fix it, it should take 3 trips to turn off the light, then 40 more to Remove the code from the computers memory.

P0440 is a generic code for Evaporative Emissionm Control System Malfunction... pretty much for all makes. It takes 1 malfunction to create a pending DTC... at 2 consecutive malfunctions the MIL(Malfunction Indicator Light){Check Engine Light, etc.} Ok, after you fix it, it should take 3 trips to turn off the light, then 40 more to Remove the code from the computers memory.Thanks (though a little late :p). I replaced the gas cap and removed the negative terminal from the battery for a few minutes and all was well again in car land. The light never came back on! Yeah! I finally fixed a car thing myself without taking it to someone and for relatively cheap.

Matt

I guess the guy who you thought "wasn't the brightest bulb in the bunch" was right. You must feel smart. :rolleyes:

I guess the guy who you thought "wasn't the brightest bulb in the bunch" was right. You must feel smart. :rolleyes:Actually I do feel smart. He also used a scan tool which told him the reason. You don't have to be a rocket scientist to use one.

BTW, that's an awesome looking car in your signature.

Thanks (though a little late :p). I replaced the gas cap and removed the negative terminal from the battery for a few minutes and all was well again in car land. The light never came back on! Yeah! I finally fixed a car thing myself without taking it to someone and for relatively cheap.

Matt

That's great, I wasn't paying too much attention to the date of your post, but since I was doing a search for more detail on the p0440 msg, instead of the generic evap system malfunction, my brother keeps getting that one alternatinig with p0457 gas cap I figured I'd check the forum... And since I had just reset his jeep, I had the info handy... The code reader is a good investment, even if you aren't into doing alot of your own work, because if you can go into a shop and say, I've got this problem, and not the time to fix it, the DTC is coming up Pxxx. At this point the person at the shop is less likely to try to rip you off, after all you know how to read codes, you might be able to catch a ripoff.

I have the same code comming up on my car, but my car will not start at all.... Is it the same thing as the other guys or is it somthing different? It to is a Pontiac.... Ironic..

Please E-mail me with the answer:




P.S. The car does NOT have a gas cap, but it drove from GA to FL "like 2 hours" fine but, then it just died.

I have the same code comming up on my car, but my car will not start at all.... Is it the same thing as the other guys or is it somthing different? It to is a Pontiac.... Ironic..

Please E-mail me with the answer:

Well I doubt it's the gas cap then since my car ran fine even though the light came on.

And BTW, I wouldn't post your e-mail on forums like that. It's just asking to be spammed.

Well do you have any ideas one what it could be??

Well do you have any ideas one what it could be??Sorry, I don't. I really don't know very much about fixing cars.

well, if you traveled any length of time without a gas cap on you could have contaminated the fuel. its usually water that gets in and does the trick. but it may just be a coincidence... more info is needed

ok so how do you fix this problem plz someone help me just list the steps and ill do it lol but seriously some one help

do u have another pressure leak somewhere, if a loose gas cap can pop this code up im sure something else being loose or leaky in the fuel system would cause this light, have u started with a visual inspection of your fuel system?

I think it's funny how this thread won't die. I haven't even had this car for over 3 and a half years, but I guess it does apply to a lot of cars. I hope it helps someone else.

P0440 is a large leak, specifically. If its not the gas cap, the vent solenoid is usually the next on the list of likely component failures. Could be the purge valve or a ruptured hose....but without a smoke machine and a scanner that can actuate all the different components, its pretty hard to really diagnose it.