Alright guys I have a 2003 Cavalier sedan automatic with 70,000 miles. My check engine light has come on and it is due for inspection by the end of the month.

Here are the specifics:

1. Went to autozone and had the code read. It comes back PO440. Evaporative emission system.

2. Put one aftermarket gas cap and one brand new GM gas cap on. Check engine light still on. I have cleared the codes after each gas cap and the light comes on a couple days after.

3. I know there was a problem with a wire harness around the ABS bracket of some sort. I do not have ABS. I checked both wire harnesses with a meter for continuity while wiggling the wires but nothing changes on the meter.

4. I do not see any leaks in the hoses and have tightened the hose that goes from the fill neck to the tank.

5. I know there is a tank pressure switch but it is at the top of the tank and If I have to check it I will have to drop the tank

If anyone has had a similiar problem and fixed it please let me know how to fix it. If I dont fix it I will just have to get a shop to fix it for me. I can do anything on my car as far as mechanical so let me know. Thanks for the help in advance.

So I am guessing no one has had the same problem as me. There has to be someone

I just fixed this problem on my parents 2001 Cavalier. Look under the rear of the car kind of by the passenger side rear wheel. There is a group of wires in black loom. On my parents' car, one of these had 2 broken wires. I will try and get a picture of the area tonite so you can see it better. All I had to do was disconnect the plugs that are affected, resolder the wires and plug it back in. After that, you need to clear the P0440 code and should be good to go. Heres the thread that helped me.

Pulling Code P0440 from Computer
http://www.j-body.org/forums/read.php?f=11&i=90253&t=90253

I have checked the wires. Is it the wire connector that has two wires in it. I didnt find any breakds in this one. Let me know which ones. Thanks for the help.

Well, there's another possibility...

At one time or another, did you have to replace the fuel pump in this vehicle. If so, did the dealer do it?

In any case, if the fuel pump had been replaced at one time, many dealers take a shortcut to do this -- instead of removing the entire fuel tank, they will sometimes loosen the tank straps and tip the tank forward enough to make room to remove the old pump. Unfortunately, when the tank gets tipped forward, it tugs on a hose that runs from the fuel tank to the evap canister. The evap canister is plastic, and so is the nipple where this hose attaches. If this fitting cracks at the base, you will get a small evap leak and this will trigger the code of which you have mentioned.

Even if your puel pump has not been replaced, this is one possibility...

That code means that there is a leak somewhere in your fuel system. However, I had the same code and the same problem. Lucky for me that the car was still under factory warranty. They checked everthing thing out and it ended up being old software that was installed on the ECM. Yes I said old software installed on the ECM. All they did is install a new OS(operating system) on my ECM and I have never had that problem since.






New Picture comming this summer.

i had the fantastic "loose gas cap" CEL

turns out it was a bad valve in the evap system.... my car was under warranty thank god

I went and had a evaporative system smoke test done. The evaporative canister was leaking. I guess it has a crack in it. They also said to replace the purge valve. They couldnt get the parts quickly so I told them I would put them in myself. I went to the dealer and picked them up. It was $150 for both pars. If I got them from gm parts direct it would of been $90. I would of loved to get them cheaper but I travel for work and I am going to Philly this week so I dont have the time to do it this week.

My inspection runs out at the end of this month. I reset the computer and he said drive it for 100 miles and come back and he will inspect it. I will let you know if the CEL comes back on. Thanks for all the help.

ok,

I put the gas cap, canister, purge valve and tank pressure sensor in. I drove 100 miles no light so I went and got it inspected . It passed!!! but the next day the light came on. Same code PO440. Can anyone tell me what else there is in the emission system. Anything on top of the tank or up in the engine compartment? Maybe the wire harness that everyone has problems with is bad. I did check it with a meter and wiggled the wires and it seemed fine. Thanks for the help so far.

i have the smae prob, got everything fixed and the cel still comes up. my mech just said i have a bad comp and i know a few other 96's like me that have the same problem.

Thanks for the input. I hope mine isnt the computer. I wonder if there were any recalls on this or TSB's. I will have to check. Thanks for the information