annoying service light wont go out. any ideas?

[LEWETHETIGER73]

So mo 06 grand prix gt says check gas cap. I have checked it, and I have replaced it. It went away for a little bit and now it comes back all the time. I replaced it with a gm part which might be the problem but now I need it done. Thanks for any tips you can give!

[BAD LS1]

Very good chance another leak source is in the evap/tank vent system. The cap is the easy likely, but obviously is prob not the issue as you found.

[lilws6]

like tom said theres a chance somewhere in the system a small leak has occured and if giving your computer a signal that the cap is loose or not sealing any more. so its probably a small leak to find.

[brotherbenn83]

Most common sources of an evap leak on a GP are a gas cap that doesn't tighten properly, a leaking vent valve and a purge valve not pulling enough vacuum (perceived by the PCM as a leak) All these parts are cheap and easy to replace. If you need a proper diagnosis, find someone with a Tech 2 and a functioning brain and they should be able to help you out.

[Yooformula]

I had the same issue and after replacing gas cap, the next step was the evap canister beneath the gas filler and the problem was solved. easy fix.

[BR3W CITY]

I had the same issue on a cavalier. Did the cap and nothing changed. We had to replace the line to the evap, and double check the little ground strap that connects to it. Same exact problem on my s10.

[LEWETHETIGER73]

Sounds like I have some new spots to look at. Thanks for the tips all!

[Firefighter Z]

I had that problem on my 03' Shitpala, I crawled underneath and banged on the Evap canister cause I at the timeI was pissed, but I checked the hoses and what not and the light went off and hasn't came back on since.

[spooln30]

If there is a EVAP leak you will get a check engine light.

[Holeshot]

A smoke test should find most small leaks in the system. This most overlooked is the filler neck which is more common then people think.

[brotherbenn83]

A smoke test should find most small leaks in the system. This most overlooked is the filler neck which is more common then people think.
Doubtful on an 06, now on a 00 J or N body I would say eff yes. Read my original post, or PM me and I will bring a Tech 2 home and fix this for you like right freaking now.

[88Nightmare]

I had a similar issue going on with my girlfriends 2002 cavalier. Ended up being a vent valve/solenoid. $17 and 5 minutes to install, then unhooked battery for about 20min to clear the computer and then ran the car through a drive cycle and passed emissions with flying colors. The problem is probably a lot easier to solve than you think.

[LEWETHETIGER73]

Well the light has been off for a while now. I had to take the battery out to change the water pump. If it comes back I will let you know. Does anyone know if there is supposed to be a metal flap inside the opening? Because there is none in there.

[brotherbenn83]

Some cars have the flap, some don't. It won't matter for the purposes of an evap leak.