12 00 ... Disconnecting and connecting battery
WARNING: This page is about a different car, the 2002 BMW Z3 and 2001 BMW Z3. However, it is still accessible from the selected car via links, so may be relevant.
Safety instructions for handling vehicle battery. Refer to 61 00 ... SAFETY INSTRUCTIONS FOR HANDLING VEHICLE BATTERY .
Disconnect Battery:
If the battery is not disconnected when working on components, cable connections etc., faults can occur in the fault memories of the relevant control units.
If the repair instructions contain an instruction to disconnect the battery before carrying out a specific repair job, for safety reasons, always follow this instruction.
CAUTION:
Disconnecting the vehicle battery will cancel the fault memories of control units. For this reason, before disconnecting the battery, always interrogate the fault memories and print out the faults on the printer attached to the BMW Service-Tester. Investigate stored faults. Once the battery has been disconnected, the radio can only be restarted with the radio code; for this reason, ask the customer for his/her radio code card beforehand. Note stored stations and restore them after connecting the battery. Stored settings of the on-board computer and clock will also be lost. On door closing systems with infrared operation, all keys must be receded.