Before disconnecting battery:

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2005 BMW 745i, 2005 BMW 745Li, 2004 BMW 745i, 2004 BMW 745Li, and 2003 BMW 745i. However, it is still accessible from the selected car via links, so may be relevant.

Switch off ignition.

NOTE: If the ignition is not turned off when the battery is disconnected, fault memories may be set in some control units.

Important!

There is a danger of mixing up battery leads: If the battery positive and negative leads are the same color and you are in doubt, follow the polarity to the battery, then mark and cover the leads.
On vehicles with radio code: After disconnecting the battery, the radio code must be re-entered. Therefore obtain the radio code card from the customer beforehand. Note stored stations and restore them after connecting the battery.
Stored settings of the on-board computer and clock will also be lost.
All available central keys must be recoded for cars with first generation infrared transmitter locking systems.