Vehicle Power (VPWR)
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
VPWR is the primary source of powertrain control module (PCM) power. VPWR is switched through the PCM power relay and is controlled by the PCM. With the ignition in the START or RUN position, voltage is supplied to the PCM through the ISP-R circuit. When the PCM senses that the ignition is in the START or RUN position, the PCM grounds the PCM relay control (PCMRC) circuit to energize the relay and close the internal contacts. With the relay contacts closed, VPWR is supplied to the PCM.