Attention: When disconnecting the wires from the battery, you can erase data from the electronic memory units.
The radio settings, clock settings and trip computer values will also be erased.
The hatch in the lid must be restarted after connecting the wires and the battery.
The data in the memory block of the diagnostic device in the engine management system will be erased.
Removal
Turn off the ignition.
Open the trunk and bend the right side trim by the handle. Remove the plastic lining from the lid.
Disconnect the wire from the battery, first the negative, then the positive.
The positive wire connection is covered by a cap that needs to be removed.
Unscrew the bolt and nut.
Remove the mounting bracket and the black battery cover.
The memory block of some electronic control units may be cleared of data.
Radios with anti-theft coding will have their code erased. Such radios can be recognized because after switching on the radio, the word CODE will appear on its display for a couple of seconds. If the code is unknown, the radio will not work. The correct code is on a special card included with the radio upon purchase or provided by the manufacturer.
The original source of the article is on the website: bmwman.ru