What causes the Evap system s to fail?

What causes the Evap systems to fail? Is this type of repair expensive? I assume I should have some one reset the check engine lite to verify that there is a problem right?

Answer:

1) What causes the Evap system s to fail? : Age , poor manufacturing, same stuff as when the vacuum sweeper fails. yes , before you ask there is a bag that can get clogged, it is more like a box though and is called a charcoal canister. The canisters job is to collect gas fumes. 2) Is this type of repair expensive? : Depends on the failure. If you just left your cap loose once and it set the light, or you need to replace the cap... I would say NO, not to expensive. Did you run over something and bust the Evap control unit, then yes I would say its gonna be expensive. 3) I assume I should have some one reset the check engine lite to verify that there is a problem right? : I think having the light reset is a wonderful Idea. And if it returns then you will know for certain. And no, you do not Have to do it if you don't want to . The vehicle will run just fine with the light on as far as the EVAP system is concerned.