Rich Grayo Jr. wrote:well, it could be anything, because what the evap system monitors basically is supposed to be a completely sealed (most of the time) containment for gasoline fumes. the vent valve opens to allow vacuum from the engine to draw the fumes into the charcoal canister, where they are temporarily held. this puts the gas tank under a vacuum, which the tank pressure sensor reads how well the tank is holding the vacuum. once the engine is warmed up, it will then open the purge solenoid, drawing the fumes into the intake to be burned along with the air fuel mix. so, what you have is a system where and stuck valve (vent or purge), any cracked line for the evap system, a bad fuel fill hose, a cracked canister, a broken wire/disconnected harness, and yes, even the gas cap can cause the computer to throw a code. now i had the P0440 code with my car (96 2.2), and tried many different things. i re tightened the gas cap, code still there after clearing. i unplugged and plugged back in the tank purge harness, code remained. i checked all the lines i could find, all looked ok, but if there was a pinhole, i would have missed it under the car (canister is up front passenger side on mine). then one day i was installing my tachometer sending unit, and realized that the valve on the back of the engine was never plugged back in after my rebuild. i plugged it in, cleared the code, and bingo! no more 0440. sorry for the long post, but i figured I'd shed some experience on this issue
