Changing the gas cap was the 1st thing we tried.

EVAP codes are one of the biggest pains to find. A shop would do a smoke test. But that'* not a easy option for you. Try unplugging the EVAP lines are the throttle body and cap both ends. Then work your way back.

I believe it is fixed. It wasn't the lines it was the fuel tank pressure sensor. It was only reading zero all the time. Swapped it out and now it reads 7.5 and as vacuum builds in the system it droppes down towards zero.

Not sure why it didn't throw a code for a bad fuel tank pressure sensor, unless zero is withing the acceptable range.

My mom'* driving it to see if a code comes back. I don't think it will.

good to hear

How did you test the FTPS? My daughters car has all the same issues you had with your moms car.

My daughters car is a 2003 Chevy Cavalier with 91,000 miles. A few weeks ago the check engine light came on with a code of P0440 (Small Evap Leak). Here is what I've done so far to try correcting it.

1. New OEM Gas cap
2. Replaced Canister vent solenoid at the rear and checked all wires for broken or damage.
3. Did a smoke test on it with a mechanic friend. Could NOT find any leaks at all.
4. Reset the check engine light 3 times now after doing each step to only have the light return on after 40 to 60 miles of driving in the car.


I'm really stumped and not sure what I should try next. Any help would be greatly appreciated!

Thank you and I look forward to correcting this problem. I hate being stumped!

What are my final options?

1. replace purge solenoid at front?
2. Could it be the engines PCM (Computer)?
3. Vapor Charcoal Canister?
4. Gas filler tube to the tank?
5. What about the Fuel Tank Pressure Sensor?

Like I said...there were NO visible leaks when we smoke tested it. We did this test numerous times!

1 you can test on the bench, you should not be able to blow through it one way or the other then when you put 12v on the pins it will change

2 probably not

3 not usually with that code

4 that would have shown in the smoke test

5 he had a scanner that reads data to see what its doing

Thank you for the reply. I will have my mechanic friend with the scanner try and read the Fuel Pressure Sensor to see if it'* bad or not.

I was able to inspect my daughters car today. I took her gas cap off and looked closely at the filler tube. I noticed a good sized crack! When we smoked tested it it was hard to get a real good seal on the gas cap end of it with the rubber cap that was supplied with the smoke machine. So, it was very hard to tell if the filler tube at the top was smoking or not. It'* a pretty good sized crack but I think I've found the culprit. I will pick up that part and swap it out this weekend. I never did install the purge solenoid because I now think after seeing the crack in the filler tube that the purge solenoid is not the issue.

that will do it

Replaced the gas filler tube on Friday. I inspected all the wires underneath with a good visual and they appeared fine. Reset the check engine light on Friday and it'* still off as of last night. My fingers are crossed!