Hi,

My mom called me and informed me that her check engine light had come on. I checked the code and it was PO440. My mom'* car is a 2002 cavalier with a 2.2 L engine.

My brother and I started with changing out the gas cap and driving the car some. It took about a week before the light came back on and it had the same code. PO440.

I went to our local pull a part and got an extra canister, vent valve, purge valve, and vacuum lines. I started by changing out the canister and vent valve. It'* the easiest to get to. My mom called me and told me the light came back on. I checked the code and this time it was a PO446. Which showed the vent valve was not functioning right. I put her old vent valve back on and changed the wire connection to the vent valve. Checking the wires to make sure they had continuity before plugging it in (seen there was a tsb out there for this).

She drove it for about a week before the light came back on. This time it was back to the PO440 code. We changed the purge valve on the back of the motor and checked to make sure there was battery voltage to the purge valve. The code has come back again.

Since this is a tough code to diagnose is it possible to attach a connector to the green evap test port and attach a vacuum gauge to see if vacuum is actually being pulled while driving it?

All the vacuum lines visually look good and don't look broken or cracked.

Does anyone have any other suggestion as to what to check or look for?

Steve

Did you check for corrosion at the neck where the gas cap goes ??

Also on my GXP I notice the little flap inside the neck will sometimes stick..

No, that I didn't check for but will the next time I go to my mom'*. Thanks for the info.

You can disconnect the vacuum line at the throttle body and cap off both ends. Drive for a while. If the code does not come back on then reconnect the vacuum line and disconnect it at the next place you can, cap it off and see if the code comes back on. Do this until the code comes back. This will help locate the problem area.

If I disconnect the vacuum line at the throttle body, it should throw a code almost immediately i would think. I guess I'm not sure what was meant by the last post. Most of the vacuum lines are hard plastic and metal. Only a couple of places are rubber and I have checked them when replacing parts.

Disconnect and cap off.

ok I'll try it. I'm going to work on it this weekend if it is not raining.

ive had a bunch of bad vacuum lines that looked fine but wouldn't hold vacuum with the vac/power bleeder tool. they are cheep and better than just eyeballing it.

I went to check on how my mom'* car was doing this past weekend. The light had not come back on and there were no pending codes stored.

I did check the gas cap fill tube for corrosion and there is none. I had a extra cap for the evap test port so i drilled it out and put a brass tube in it so I could hook up a vacuum line to it while driving to see if it was actually getting vacuum. I removed the schrader valve and put the cap on and hooked up the gauge and away I went down the road.

When the throttle plate is open during acceleration or cruseing down the road it had 1 - 2 inches of vacuum. Once the throttle closed it went to zero.

So far so good. My mom is going to call me if the light comes back on.

Good to hear.