There are entirely too many computer-controlled electrical interconnections in new cars. I'm sorry, but I can't grasp why the PCM needs to be notified by the power window module via the BCM that you're simply lowering a window. It's beyond me.
I have this one car on which--you won't believe this--the power window wires run from 12V+ key-on, to switches, to the fucking window motors. How could that possibly work?!
Of course, for several years now manufacturers have disabled comfort/convenience options like AC, cruise control, and remote start if the "Check Engine" light is lit. I can hear the Soup Nazi: "NO CRUISE FOR YOU!" Because, y'know, you don't actually own the car--you just paid to maintain it whilst you borrow it from the EPA and insurance companies.
Mrs. resto's '21 Jetta cut the heated seats, remote start, high setting on the heater blower motor, 3 out of 4 power windows unless vehicle was stopped, and a whole lot of now-forgotten goodies when the "check engine" light came on.
A module that controlled a power vent for the fuel system had an intermittent fault. Unfortunately, techs could never find more than a thrown code whenever it went in for the problem. Turn off the light, then a day or two later it would come back on. Warranty wouldn't cover repair/replace unless an active problem was detected at time of service. Back and forth to the dealer all last January and February meant no remote start, high-defrost setting setting, heated wheel or seats through the coldest months. Her rheumatoid doesn't like cold vehicles...
Five dealer visits, until one of the techs decided to hook the scanner up while the car was outside and cold from sitting. Turns out the heated dealer bay let the power vent function normally, so no faults were detected.
Then, the module was found to be on back-order. She almost dealt the car off, she was that ticked with it.
The dealer searched until a module was found at a dealership in northern BC. Apparently, the only module in Canada...
Of course, I had to remind her how fast my old big-block 300 heated up, and that my '79 Volvo had heated seats, and warm air from the heater within two minutes of start up.
Yeah... I'm THAT kind of husband.
