12 00... Instructions for disconnecting and connecting battery

WARNING: This page is about a different car, the 2005 BMW Z4, 2004 BMW Z4, and 2003 BMW Z4. However, it is still accessible from the selected car via links, so may be relevant.

Observe safety instructions for handling vehicle battery .

Before disconnecting battery:

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.

General notes on disconnecting battery:

Do not disconnect battery leads and leads from alternator and starter motor while engine is running.
Cars with IBS on battery negative terminal:
Do not under any circumstances pull/lever off pole shoes by force.

Do not under any circumstances release socket-head cap screw of IBS.
Detach terminal of battery negative lead from car battery and second battery if fitted. Cover battery negative terminal(s) and secure.
When work is carried out on the electrical system, faults may be caused in the fault memories of some control units when the battery is connected.
When fitting terminal for battery negative lead. Tightening torque, see 61 21 1AZ in GENERAL ELECTRICAL SYSTEM - TIGHTENING TORQUE .

After connecting battery:

IMPORTANT: After a power supply interruption some equipment is disabled and must be reactivated.
Likewise, individual settings are lost and must be activated.
Example:

Vehicles with AFS only: Activate steering angle
If necessary, activate power windows
If necessary, activate mirror with compass