Yes, I searched through the other posts on the IWE problems. 30 minutes of reading and didn't find the information I was looking for, maybe I needed to read for 31 minutes....
Anyway, son-in-law's 2020 STX has the usual noise first starting out, goes away after cycling 2wd to 4wd and back.
I tested all the lines, and the actuators- all hold vacuum well, actuators engage/disengage well when vacuum is put to them manually.
22in vacuum at the engine side of the solenoid, nothing at the actuator side in the shop, but of course it needs to see a speed signal before it will energize the solenoid.
Road test (+/- 5miles, 2wd, with gauge attached): 0 to 2 miles no vacuum on load side, turned around, within 1/4 mile the gauge sprung immediately to 17-20in for a few hundred feet, then immediately dropped back to 0, few hundred feet back again to good vac, then back to 0, then finally went to very good 20+in for the rest of the trip.
Pulled into my shop and left idle- vac held for several minutes. Cycled 2wd-4wd-2wd-4wd, vac came and went each time with a roughly 5 second delay.
Engine off, held vac for 5 second, solenoid audibly clicked, and vac went to 0.
*** I have to assume this is normal operation, but here, other forums, and Ford diag doesn't seem to specify time to activation, or the cycling back and forth on it's own***
Last note: tried to test the solenoid with a Power Probe and the tip of the probe just got instantly very hot but the solenoid never switched, no matter which direction I had +/-. I initially took this as a seized/shorted solenoid, but the road test proved it does work.

Thoughts from the gallery?

 

It sounds like you need to replace the solenoid valve, 7L1Z-9H465-B. It is not overly expensive.

If you have FORScan or a high-end diagnostic tool you can control power to the solenoid using TCCM PID IWE_OS. You can then monitor the vacuum as you switch the power on and off. This should tell you whether the valve is working properly or not.

The valve solenoid should have 44-70 ohm resistance.

 

I have no idea what a power probe is to test a solenoid, the 12v hot lead to the solenoid is hot all the time, the system supplies a ground path to the other side of the solenoid when it is appropriate. A bad connection to either side could cause it to drop in/out.

 

I can check the resistance, but don't have access to anything more than a generic scanner. I'll see what I can find in there.
Do you know if the multiple cycling before finally disconnect is normal, or should it be one time and it's done?

 

Power Probe is a 12v tester which supplies power and ground to any electrical device, independent of the vehicle's systems. Basically a jumper with a switch and a beeper signal....