SES Error Code 0440

[Stacy13]

Polling all OBD2 gurus. Recently noticed the SES light on in my 2002 Grand Am SE1(V6). After scanning, the code 0440 "Evaporative Emission Control System Malfunction" appeared. What exactly is this implicating? Could it be just the PCV or EGR? Let me know, thanks. Have a great extended weekend to all.

[foff667]

its a part of the evap system...start by checking that your gas cap is tightened down.

[JL8Jeff]

It could be the charcoal cannister going bad, it could be the solenoid valve that mounts on the intake manifold, it could be the gas cap, it could be the hoses getting hard and cracking which allows too much air to leak into the EVAP system. I just went through and replaced most of the stuff on my car. The parts are not real expensive but it's a PITA getting to some of it.

[Ian]

ususally when its the gas cap it will be evap large leak or evap medium leak, but it still could be the gas cap. but a malfunction most of the time is the solenoid or purge valve.

[Stacy13]

Thanks for your replies. As it turned out, it was indeed the gas cap not properly secured by the attendant after fillup. Chalk this one up for experience. Simply put, the EVAP system monitors the fuel tank pressure via a sensor upon startup and while driving. It then draws fuel vapors out of the tank into the charcoal canister where it's then routed to the engine. With lower than usual pressure, the PCM will trigger the SES light.
For those with similar problems in the future, focus your attention to the real culprit, the gas cap in this scenario before wasting time in the engine compartment like I did. Thanks again.

[foff667]

:takesbow: