Does the 04 models have self diagnostic test by turning the the ignition 3 times like on the 97's and some other years?

Would that trigger code read of potential issue regarding a Check Gas Cap light?
I know it works wonders with the Check ENgine light.

It may be worth a shot. The Dealerships will charge at least 90 just to hook it up.

my 2 pennies

Chef Mark

Life is like a hardcore offroad trail...put it in 4-lo and get over it!!

97 TJ, (R.I.P.4-Cyl) 5.3 Vortec Gen III, NV4500, Ford 8.8 Rear, 30 Frnt, 33" BFG MT, 4.25" Susp, 2"Bdy, OBA, Rk Hrd 4x4 Cage, bunch of other cool stuff.