If your looking for the service port, I would think that your using it to check for an EVAP leak, so you might want to consider using the smoke system and use the gas tank adapter, and check for what valves and related ports, or what ever that you need to do prior to testing EVAP system, to see if they need to be closed or open, this is of course if there is no service port available, some vehicles do not have them so you have to use different set ups for testing.