"Tighten Fuel Cap"

[DooWap]

I have a 2005 Silverado with a little over 100K on it. The other morning I start up my truck to go to work and the SEL is on. Not the best way to start the day. Then as I pull out of the drive, the message "Tighten Fuel Cap" displays. So I pull over and find that the gas cap is on nice and tight already. Light is still on though. Even took it off and put it back on. No change.

Anybody have this issue? Solutions?

[Huskie]

Happens with my 04 each once in a while. It usually takes 20+ starts for the light to go off. I'd clean up the cap a bit and see if it goes off. Some of the parts stores will read the code for you and shut it off. As long has it is not running rough you should be ok. I'm not a mechanic but have had it happen a number of times with the last three trucks that I had. The first time I had the shop read it. 100 bucks later they told me it was the gas cap!!!

[Scott K]

It means there is a leak in the evap system. They put a gas cap light on because that is the most common reason for it. if the cap seal looks good, and the filler neck isnt all dinged up, then it is time to bring it in and have the pros check it out. It can be anything from a bad sensor, to a leak in the system.

[Jeremy airjer W]

yup, Usually its a large evap leak code P0455 (I think).

You could do this..

1. Find the EVAP vent solenoid. I believe it is tucked up by the spare tire. You could locate the charcoal canister. There will be a larger rubber/plastic line connected to it. Follow that line back to the vent solenoid.

2. the vent solenoid will have a two wire connector. One wire is orange and should have power to it all the time and the other is white and is grounded by the PCM when the solenoid is commanded closed.

3. Remove the solenoid from the vehicle.

4. supply your own power and ground to the terminals and blow through it. If you can blow through it it is bad. If you don't here it click it is bad.

5. if there is no power at the connector check the 4WS fuse in the under hood fuse block. If it is blown replace the fuse and the solenoid.

[DooWap]

Thanks for the advice guys. I think I'll go see if I can pull the codes on it and narrow down the issue. Might be a nice little weekend project that I really didn't need.

[ottertailguy]

It happened to my 05 chevy. I found online that said put some oil on the gasket inside the cap. It did the trick within 1 mile after I did it.