[bnabholz]

I have this problem on my 2006 Civic. I wondered if it was a GPS week rollover issue. Week numbers are 10 bits and roll over every 1024 weeks[0]. Jan 2nd, 2022 was the start of week 143 on the 2019 epoch. They may have programmed it such that "for week numbers 143-1023, assume the 1999 epoch is used; for week numbers 0-142, assume the 2019 epoch was used." Without having the clock "remember" the latest year it has seen from GPS (e.g. by writing into EEPROM), it would to be limited to 19.6 years of useful life. It's a matter of choosing which epoch they wanted to associate groups of week numbers with.

There's something more to it though, since if it was using the wrong epoch, the date would be off but the time would still be correct. Week 143 on the 1999 epoch would be May-ish 2002 but the observed behavior is that the clocks are all stuck around 4:00 on Jan 1, 2002 (and shown as a Sunday, when it was actually a Tuesday). Since the 1999 epoch started on Aug 22, 1999, I am wondering if that's another piece to the puzzle and why they suggest it will auto-correct in August.

It's an interesting problem and I'm curious about the root cause, but in reality this will just be the push I need to get a newer radio that can do CarPlay/Android Auto.

[0] https://en.wikipedia.org/wiki/GPS_week_number_rollover