Abstract: The present invention is directed to a liquid dispensing system having a valve subsystem and pumping subsystem. The valve subsystem is configured with a pressure sensor subassembly having an electronic interface to determine the liquid level in a vehicle gasoline tank or other liquid vessel. The valve subassembly of the present invention may include a piezoelectric subassembly to detect pressure changes at a nozzle subassembly to shut off the liquid flow through the valve subsystem and from the pump subsystem. Aspects of the present invention may also sense when the nozzle subassembly has been partially removed from a liquid tank fill tube. The present invention may include wireless technology to transmit information from the valve subsystem to the pump subsystem to prevent an overfill condition in the vessel. For example, the pump subsystem will not pump without confirmatory signal from valve subassembly that all components are operating properly.