So I went to the sticky: "What does your CEL mean" and This one is the one that my car has.

DTC P0440 Evaporative Emission (EVAP) System

I was thinking it could be the gas cap so I got a new gas cap... since it's done this a million times. Its not the gas cap because they cleared the CEL when I got the new gas cap. and it came back on the next day.

Meh, it could be a bunch of different things... I hate to think I have a leak in a hose or something of that sort. Cuz then i'd have to find it and fix it.

Please help me

The fuel system is pressure tested when certain conditions are met, example car is at operating temp, the fuel tank is above 1/4 and below 3.4 full.

Anyways during the pressure test if it sees a leak it will set a code.




- 2004 Cavalier - 124k, owned since new