engine lights on 2004 Honda Accord

the engine lights goes on sometimes after I fill the car and understand the cap does not get on tight as they told me this when had it checked. I try to get it on tight but still comes on sometimes

Asked by for the 2004 Honda Accord
1 answer
The gas cap has a "ratcheting" mechanism built into it. When you turn the cap to lock it you should hear a clicking sound. I tell people to turn it another 180 degrees after they hear the first click.
Many auto repair shops have a "smoke machine". It is used to put a non flammable smoke into the gas tank to check for leaks. I wonder is the neck of the gas tank damaged that the cap seals on or is the cap its self defective?