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Hi thank you for your question hope this helps.
Diagnostic Trouble Code (DTC) 543 indicates a fuel pump secondary circuit failure between the B(+) supply and the Fuel Pump Monitor (FPM) connection to the power-to-pump circuit. 99 times out of 100, this DTC results in a no-start condition.
If the engine starts and runs, the it is a pretty good indication there is a problem with the Power train Control Module (PCM).
NOTE: Due to the internal circuitry of the Power train Control Module (PCM), a left/front Heated Oxygen Sensor (HO2S) signal short to power could produce a Diagnostic Trouble Code (DTC) 542 or 543. So be for replacing the PCM replace the Front Drivers side 02 sensor. But with your no start and engine stalling i am thinking PCM failure.
Hope this helps
First a junk yard PCM is a crap shoot you wont to look for one that is not from a truck that has been in a reck. Yes the a ford dealership can test the PCM.
My trick for getting the bottom nut is 1/4 inch ratchet and a long extension.
i would not thing a ground would give this problem because in this case the battery power is not getting to the fuel pump circuit witch is feed throw the PCM. but you could give it a try stranger things have happened.
As for the ICM you would have different problem's along with Diagnostic codes. something along the lines of bad communication codes or faulty communication codes