when I get the check fuel filler cap, I'll take a cloth, wet it with alcohol and clean the metal filler neck where the screws onto; then I'll use some chapstick and apply it to the o-ring of the cap. Code usually clears off after a few key cycles.
The occasion where that did not clear the code, replacing the white filter on the Evap is easy to do
worst case is a broken connection on the gas tank.
To read the code you can try this (from Quadratec)
Insert your key and turn the ignition to the On position without starting the vehicle. Then, push the key into the ignition cylinder and (while holding it in) turn it to Off then On three times - making sure to end in the ON position. The reason to keep the key pressed in while turning is to avoid the key from catching along the way and interrupting the process. When done correctly, as the key finishes in the On position, your odometer will read a series of six dashes, then display a Diagnostic Trouble Code shortly after. Write down this code and reference from the list below.
Now, some people have noted that they are not able to pull the code by moving the key from On to Off, and instead have found success going from On to Acc and then back.
