It could be the settings are stored in NVRAM or FLASH (the service manual specifically mentions both the ECM and ABS retaining stored trouble codes over power down) and the clock could have a supercapacitor.
With today's technology, a consumer grade Dallas (now Maxim) RTC could live for days off a small supercap.
With today's technology, a consumer grade Dallas (now Maxim) RTC could live for days off a small supercap.
