DTC P1220: Fuel Pump Control Module (FPCM): Description
WARNING: This page is about a different car, the 2009 Infiniti FX50. However, it is still accessible from the selected car via links, so may be relevant.
When driving conditions demand a decrease in fuel supply, the fuel pump control module (FPCM) reduces the supply voltage to the fuel pump. When driving conditions demand an increase in fuel supply (during engine start, low engine coolant temperature or high load), the supply voltage to the fuel pump is increased.