Abstract: An apparatus is provided for detecting the presence of a vehicle equipped with an onboard refueling vapor recovery system. The apparatus has a body that is equipped with an inlet fluid port and an outlet fluid port that is in fluid communication with the inlet fluid port. The body also has an inlet vapor port that is in fluid communication with the outlet fluid port. The apparatus further includes a vacuum chamber that is located within the body, and that is in fluid communication with the vapor port and the outlet port. The apparatus has a vaccum activated detecting switch coupled to the body that is in fluid communication with the vacuum chamber. A vacuum-generating nozzle is coupled within the body between the inlet port and the vacuum chamber. Fuel may be provided to the inlet port and routed through the nozzle to create a vacuum within the chamber.