Vehicle Buffered Power (VBPWR)
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Ford RV Cutaway, 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
VBPWR is a regulated voltage supplied by the PCM to vehicle sensors. These sensors require a constant 12 volts for operation and cannot withstand VPWR voltage variations. VBPWR is regulated to VPWR minus 1.5 volts and is also current limited to protect the sensors.