Disconnecting the negative battery cable (starter unit battery)

NOTE: RISK OF DAMAGE 
Damage to battery terminal, the safety battery terminal or the intelligent battery sensor (IBS). 
Damaged battery terminals can lead to malfunctions or vehicle electrical system faults. 

• Detach battery terminal from battery pole. Do not pry off using a tool.

Courtesy of BMW OF NORTH AMERICA, INC.

• Slacken the nut (1) on the negative battery terminal.
• Detach the negative battery terminal (2) from the negative battery terminal.
• Put the battery ground lead to one side and secure it.