My VX has that code constantly popping up, and a couple of mechanics have found nothing wrong with the evap system. The theory is that there is an electrical gremlin causing the trouble code, but I have not had time or $$$ to chase it down. I tried being sneaky and clearing the code a day before getting the VX tested, but (even though it didn't "fail") it did not successfully get through the testing... I brought the VX in to my mechanic near the testing facility, and he got it passed. However, 0440 reared it's ugly head again soon after. Good luck!