FJCruiser Power Windows Dead After Battery Change

Indeed it could. Did you try performing a window reset procedure? Sometimes disconnecting the battery can cause the window motor's upper and lower limits to be lost. Do the windows go down at all, or are they completely unresponsive?

Completely unresponsive. I assume there is a procedure, but what exactly does a window reset entail?

Given the unresponsiveness and the error code, a reset might work, but it sounds like the initialization procedure is failing, indicating a deeper issue. You may require professional assistance to diagnose whether the regulator is faulty. This is to prevent further damage to your car electronics.

Thanks for the advice. I took it to a workshop, and you were spot on. The window regulator initialization was unsuccessful. It cost 290€ to resolve.