General notes on disconnecting battery

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 BMW 328xi, 2012 BMW 328i, 2011 BMW 328xi, 2011 BMW 328i, and 2010 BMW 328xi. However, it is still accessible from the selected car via links, so may be relevant.

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 installing battery terminal: Tightening torque 61 21 1AZ .