Myth 1: Have changed the battery and was told the following: The software in a Merc is so sophisticated that it charges an older battery less/more aggressively and that means one must use the diagnostic to inform the ECU of the fact of a brand new battery? All my manual says is that the Varta battery should be charged with a voltage of less than 14.3V. A cheap gadget from Aliexpress I plug into the cigarette lighter with two USB ports tells me the charging voltage and it is in range. But how about the charging Amps?

Myth 2: Changing the oil of the auto gear box meant asking Dr Google for help and one point was made to inform the ECU afterwards of having flushed the oil as the junk in the oil definitely results in more friction? Myth or fact?

Myth 3: Similar to a PC, which has a button battery to keep the OS settings, a Merc is also supposed to have one to keep the ECU settings (parameters) and that battery may also get old and fail? If so, where is it in a C220 CDI W204 and how do I change it? How do I know when to change it? Thanks.