The Check Engine Light turned on in my 2000 SLE V6. I had the code diagnosed and one of the possibilities was a loose fuel cap. When I unscrewed the fuel cap, I did not hear the pressure release as usual. I tightened the fuel cap and drove for a while. I then disconnected the negative from the battery to reset the Check Engine Light. The Check Engine Light did not turn on again. I went to the gas station to refuel and when removing the fuel cap, I heard the pressure release as usual. As it turned out, it was just a loose fuel cap.