Powertrain control module power - 2000 Ford Expedition

Power control module and usually passenger side behind kick panel or sometimes under hood in engine bay

Doesn't have one . all electronically controlled . An it was a vacuum modulator valve.
Transaxle Electronic Control System Electronic System Description
Shift timing, shift feel (line pressure) and torque converter clutch control in the AX4S are controlled electronically by the powertrain control module (PCM) (12A650) and its input/output network. The transmission control is separate from the engine control strategy in the powertrain control module, although some of the input signals are shared. Some input signals come from the engine-related sensors, for example, mass air flow sensor (MAF sensor) (12B579) and engine coolant temperature sensor (ECT sensor) (12A648) to give the powertrain control module an idea of the load and climate under which the engine is operating. Some other inputs are based on driver inputs, such as accelerator pedal position which is related to the powertrain control module by the throttle position sensor (TP sensor) (9B989). Still other inputs are provided by the transaxle itself, from sensors such as the vehicle speed sensor (VSS) (9E731), transmission range (TR) sensor (controlled by the placement of the selector lever) and the transmission fluid temperature sensor. Using all of these input signals, the powertrain control module can determine when the time and conditions are right for a shift or torque converter clutch application. The powertrain control module can also determine the line pressure needed to optimize shift feel. To accomplish these functions, the powertrain control module controls five electronic solenoids - three on/off solenoids for shifting, one pulse-width modulate solenoid for torque converter clutch control and an electronic pressure control (EPC) solenoid for line pressure control.

Do you mean the transmission control module ? It is incorporated into the engine control module . PCM - powertrain control module .

Powertrain Control Module (PCM) (L36/L67)
Left front of the engine compartment, inside the air cleaner assembly
Engine Controls Component Views in Engine Controls - 3.8L
Powertrain Control Module Connector End Views in Engine Controls - 3.8L
Powertrain Control Module (PCM) (LG8)
Left front of the engine compartment, inside the air cleaner assembly

Hi mate start at the easiest point which will be to check your EARTH to make sure everything is earthed.

Possible causes
- Faulty Powertrain Control Module (PCM)
- Powertrain Control Module (PCM) harness is open or shorted
- Powertrain Control Module (PCM) cicuit poor electricl connection
- Low battery voltage

A power-train control module, abbreviated PCM, is an automotive component, an electronic control unit (ECU), used on motor vehicles. It is generally a combined control unit, consisting of the engine control unit (ECU) and the transmission control unit. Powertrain control module. This wiki page will explain what you need to understand.
Powertrain control module

The crankshaft position sensor identifies position of the crankshaft to the ignition control module (ICM), engine control module (ECM) or powertrain control module (PCM)

When not replaced, vehicle could experience no- or hard start, long crank time, misfire, lack of power, excessive hydrocarbons in oil, spark plug fouling, catalytic converter failure, poor fuel economy, CEL/MIL illumination or intermittent shutdown.

The camshaft position sensor identifies position of the camshaft to the ignition control module (ICM), engine control module (ECM) or powertrain control module (PCM)

When not replaced, vehicle could experience no- or hard start, long crank time, misfire, lack of power, excessive hydrocarbons in oil, spark plug fouling, catalytic converter failure, poor fuel economy, CEL/MIL illumination or intermittent shutdown

Powertrain Definition: Internal Control Module Read Only Memory (ROM) Error P0605 FORD Description The ECM consists of a microcomputer and connectors for signal input and output and for power supply. The ECM controls the engine.
Most common cause of this code is a defective ECM (Electronic Control Module), in your year the part is known as the PCM (Powertrain control module)

U0140 Lost Communication With Body Control Module

This generic "U" trouble code applies to all car makers and indicates a problem between the PCM and the body control module. This is likely the result of a problem in the data link between the two modules.

Is the U0140-LOST COMMUNICATION WITH BODY CONTROL MODULE also set?
YES: Follow the diagnostics for U0140-LOST COMMUNICATION WITH BODY CONTROL MODULE
Perform the POWERTRAIN VERIFICATION TEST. See: Verification Tests\Powertrain Verification Test
NO: Replace and program the Powertrain Control Module.
Perform the POWERTRAIN VERIFICATION TEST. See: Verification Tests\Powertrain Verification Test

Good luck.

All the modules are connected together to communicate with each other via the PCI bus. It is possible that one of the modules is pulling the bus down. If the vehicle won't start it could be any one of the modules. It will be a process of elimination to find the faulty one by disconnecting them one at a time.