perhaps your dying battery is the cause.
When the battery is weak, the management shuts down modules that are not essential in order to improve the battery life left. perhaps the rear view camera is one of these non essentials.
When mine was going around xmas, my going home lights stopped and other little things stoppedrrunning as usual, thn the abs module started throwing errors as the modules no longer had enough juice going to them making them act real flaky, but the car was starting fine.
Replaced the battery and coming home lights after a few days started to come on again and the errors stopped. Some recomend if it has run so low modules are no longer booting to save life, then you need to use a vag com after changing the battery to tell the car it has a new one in but i luckily did not.
