Apparently one of the most common service calls Volvo dealers get is the
"Fuel Filler Cap Loose-Open" message, with the yellow triangle light.  I
read in the manual that you can get that error if the gas cap is not tight
after refueling, or if you refuel the vehicle with the engine running.

We are now getting that error, however our fuel filler cap is tight, and we
always tighten it when we fill up.  It clicks many times.

I read it somewhere on the internet, that it could take up to a few
days/weeks for the error to actually show up. Therefore people think back
wondering if they may have left it open or something.

How do we avoid this error message, when we are pretty sure we're tightening
the gas cap until it clicks many times?

Will the error cancel itself after a while?  Is there a way to make the cap
seal better?  There's a gray rubber O-ring seal that goes against the metal
filler pipe.  Wondering if just a bit of plumber's grease would lube the
O-ring and make it seal better.  Or does the filler cap need replacing?

Thanks for any info.

Mike