do u have a spare RCM.. that is a must everyone carries 1 or two
you can disconnect the batt ,drain it down , The car ,, by opening and close the door 3 to4 times
reconnect batt code gone if that does not work replace the rcm. here r a few other things

• Gas cap replacement ,,,,,,,,,,,,,,,,,,,,,,,,, i doubt it
• EVAP line replacement,,,,,,,,,,,,,,,,,,,,,,, check for broken hose
• Replace charcoal canister,,,,,,,,,,,,,,,,,,,replace
• Replace the fuel tank ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,we have had a few tanks collapse
• Replace the vent control valve,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, u did that right