Module, Fuel Pump: Operation

Voltage to operate the electric pump is supplied through the fuel pump relay.

Check Valve Operation:  The bottom section of the fuel pump module contains a one-way check valve to prevent fuel flow back into the tank and to maintain fuel supply line pressure (engine warm) when pump is not operational. It is also used to keep the fuel supply line full of gasoline when pump is not operational. After the vehicle has cooled down, fuel pressure may drop to 0 psi (cold fluid contracts), but liquid gasoline will remain in fuel supply line between the check valve and fuel injectors.Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine off) is a normal condition. 

The electric fuel pump is not a separate, serviceable component.