p440 code 2002 bonneville se

i have replace the fuel cap and purge valve on front of engine still getting p440 code. i have over filled tank in past. can anybody help me fix this so error code does not come up again?

check the vent solenoid. with it unplugged you should be able to blow through it. If you supply power and ground it should close and you should not be able to blow through it. Also make sure there is 12 volts to the solenoid with the key on. There is a separate fuse just for this and I have had many of them blown.

The other option is there is a problem with the Fuel Tank Pressure sensor. Unlikely but possible.

is the solinoid you are talking about under the hood?

Nope. should be under the car near the gas tank. If its not attached directly the the evap canister than follow the largest diameter hose on the canister to the vent solenoid. Sometimes there mounted up by the filler neck also.

thanks i will check it out in a few days and let you know. may remove the canister if other things check out ok to see if fuel got in it and gummed things up.

purge valve at fuel tank is ok, did a bench test worked perfect. where is the fuse? under the hood or under back seat? pulled every fuse did not see a bad one. do you know how this fuse is labled? i did not see on fuse directory anything that stood out that would be for the purge valve. still have to verify there is power to the purge valve when the key is on. i will check this in a day or two. where on the fuel tank is the pressure sensor?

Go find someone that has a smoke machine and this is the best way to find EVAP leaks instead of throwing parts at it.

Page 6-74 of your owners manual. Mini fuse #11 labeled ventilation solenoid. in the fuse block under the back seat. Be careful with your terminology. It is a vent valve/solenoid not a purge valve. They are two different things. The fuel tank pressure sensor is on top of the fuel pump module. You will need a scan tool to see what it is doing. You may also need a scan tool to turn on the vent valve/solenoid to check for power.

At this point you have pretty much done what you can except check for power and I would have to agree with wafrederick you need to seek professional help.

you guys are great thanks for all of your help. I will post once i find what the problem is.

FYI went under car and found purge solenoid neer fule tank. the electrical connection had a little corosion in it cleaned it up reset computer problem gone.

purge valve at fuel tank is ok, did a bench test worked perfect. where is the fuse?


Hmmmm, didn't see the corrosion when you bench tested it?

The purge valve is under the hood, The vent valve is in the back of the car. Are we sure we are talking about the same thing?

you are right it was the vent solenoid, was talking to a family member, he used to work for GM, he told me that GM has a problem at times with some of the connectors. he told me to look carefully at the connections, the corosion was minimal but just enough to cause a problem, thing have to be perfect or you will have intermitant problems