p0440 code

[sierra]

I need help with a couple of questions.Is the vent valve located on the
gas tank supposed to be open when energised or closed.
Should the purge valve located on the intake manifold seal completely,seems like that would not matter as long as the valve opens in order to pull a vacum and vapors from fuel tank.Last question how can you test the vacum sensor located on the top of the fuel tank pump unit.

Would greatly appreciate any and all help.


Sierra

[sunsetorangess]

How many miles are on the vehicle and mods? Did you check your gas cap?
J

[DaddySS]

Like stated above, how long have you had the code? First thing to check is the gas cap.

[sierra]

thank you for responding.The car has 59,000 miles on it and has no mods.
Yes i replaced the gas cap first,but after clearing the code it came right back on.I have since removed the gas tank and checked all vacum lines for a leak
and found none the only part i could find leaking was the purge valve.I replaced it.According to a GM print out that i was able to obtain the purge valve should have set a different code.The dealership service dept. tells me that there is no way to test the vacum sensor that is located on top of the intank fuel assembly.I f that sensor is not working your going to get a440 code even if there is no vacum leak.I do not no what else to do.

[2001NBMZ28]

Have you looked up the code at www.gearchatter.com for any other diagnostics?