[SwissXC90]

Originally Posted by BenB

I've only had my XC90 a few days and noticed today an electrical gremlin! When I wound the window up on the passenger side it would drop itself again, to the exact point it had been lowered to. If I creep it up a little at a time, trying to fully close it again will always drop it back to the new position. I just couldn't close it. However closing it using the driver's window controls it closed fine and stayed there.

Is this a known issue? Could it be just my passenger window switch? Or something more serious?

It is the jam detection - the motor thinks the window is jamming.
Happens due to age as the entire window mechanism is no longer operating as freely as it did when new,

Ensure the glass is clean in the guides
Ensure the guides are clean
Try a spray of some light lubricant in the guides, like silicon

Then if that does not work reset the window stop detection by pulling the fuse for the door controller out while the windows is going up or down. This forces the door controller to lose its memory.
Refit the fuse.
Then get the door controller to relearn the window jam detection by bringing the window up, and continuing to hold the window switch in the up position until the window motor stops. This has now reset the end position / jam detection.