Vehicle Buffered Power (VBPWR)
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The VBPWR is a PCM supplied power source that supplies regulated voltage (10 to 14 volts) to vehicle sensors that run off 12 volts but cannot withstand VPWR voltage variations. It is regulated to VPWR minus 1.5 volts and is voltage limited to protect the sensors.