Nintendo no longer repairs Wii U consoles because, according to its official Japanese X (formerly Twitter) page on July 3, it no longer has the necessary parts in stock.
The Wii U feels like a relic of the past to many as of 2024, and no one seems as keen to forget that the failed console ever happened as Nintendo. The fact that the Nintendo Switch so quickly replaced and overshadowed the Wii U makes it easy to forget, however, that the Switch predecessor launched only a year before the PlayStation 4 and Xbox One, consoles that Sony and Microsoft continue to support to this day adamantly while Nintendo has cut all ties with the Wii U, and now no longer even repairs the console.