To be honest I don't know....but I did turn it for the 3 last night....let me double check this morning and see what happens today...hate to take it to the dealer for such an issue.

 

If the code that is setting, is a small leak in the evap system, then the cause COULD be the gas cap. But the gas cap is just one of many things that could be wrong with, ranging from rusty filler tubes, loose clamp, bad o-ring on the sending unit, cracked hose, bad canister purge valve......pretty much anything to do with the evap system. There are special tools and smoke machines that can be used to pin point the probllem very easily.

 

Are you saying that since last week the check engine light has not turned off? If thats the case, it could be the gas cap, when mine did that I called my brother (a tech) and he said it takes a certain number of cycles of turning the engine on and off (I wanna say 30-60) before the light will go out. If it went out between last week and now, and is coming back, then I have no idea.

 

Not that many! Its like 3-5 key cycles and on some cars its 30 driving miles.

 

Haha, its been a few years/beers since then,I thoughtI remembered 30-60 .

 

The older vehicles (pre 2000) would require many (30+) start cycles to reset the SES light if the cap was left loose but newer vehicles (up to 2006) require just a few driving trips with the cap properly installed to turn the light off.
The 2007 and 2008 models will actually display the words "TIGHTEN GAS CAP" in the DIC display.

 

Not to hijack the thread, but just curious on the newer evap systems...

Dave, have the evap systems evloved that much that it knows if if it the cap that is loose? Or could a bad o-ring in the sender still be a culprit? I haven't worked on these systems for a fewyears but wouldn't it work on the same principle of previous years? A loss of vacuum after a purge?

 

Thanks Dave, thinking back, it very well could've been my 96 sierra that did it. (Only had it for ~8 months)